Human Body And Disorders Exams Prep Test

1. Prior to chemical tests for glycosuria, clinicians checked for sweetness of the urine as a sign of

Diabetes insipidus.

Acute glomerulonephritis.

Diabetes mellitus.

Renal calculus.

Pyelitis

Prior to chemical tests for glycosuria, clinicians checked for sweetness of the urine as a sign of diabetes mellitus. Diabetes mellitus is a condition characterized by high levels of glucose in the blood, which can lead to glucose spilling into the urine. This excess glucose in the urine can give it a sweet taste. Therefore, the sweetness of the urine was used as an indicator for the presence of diabetes mellitus. The other options listed are unrelated to the presence of glucose in the urine and do not cause sweetness.

Explanation

Prior to chemical tests for glycosuria, clinicians checked for sweetness of the urine as a sign of diabetes mellitus. Diabetes mellitus is a condition characterized by high levels of glucose in the blood, which can lead to glucose spilling into the urine. This excess glucose in the urine can give it a sweet taste. Therefore, the sweetness of the urine was used as an indicator for the presence of diabetes mellitus. The other options listed are unrelated to the presence of glucose in the urine and do not cause sweetness.

2. This byproduct of protein catabolism constitutes approximately one-half of all nitrogenous waste.

Urea

Creatinine

Ammonia

Uric acid

Azotemia

Urea is the correct answer because it is a byproduct of protein catabolism and makes up about half of all nitrogenous waste. Urea is formed in the liver when proteins are broken down and is then excreted by the kidneys in urine. Creatinine is also a waste product of muscle metabolism, but it is not as abundant as urea. Ammonia is a toxic waste product that is converted to urea in the liver. Uric acid is a waste product of purine metabolism and is excreted in urine. Azotemia is a condition characterized by high levels of nitrogenous waste in the blood.

Explanation

Urea is the correct answer because it is a byproduct of protein catabolism and makes up about half of all nitrogenous waste. Urea is formed in the liver when proteins are broken down and is then excreted by the kidneys in urine. Creatinine is also a waste product of muscle metabolism, but it is not as abundant as urea. Ammonia is a toxic waste product that is converted to urea in the liver. Uric acid is a waste product of purine metabolism and is excreted in urine. Azotemia is a condition characterized by high levels of nitrogenous waste in the blood.

3. Which of these correctly traces blood flow from the renal artery into the renal cortex?

Arcuate a. → interlobar a. → afferent arteriole → interlobular a.

Interlobar a. → interlobular a. → segmental a. → arcuate a.

Segmental a. → interlobar a. → arcuate a. → interlobular a.

Afferent arteriole → interlobular a. → arcuate a. → interlobar a.

Segmental a. → arcuate a. → interlobar a. → interlobular a

The correct answer traces the blood flow from the renal artery into the renal cortex in the following order: segmental artery, interlobar artery, arcuate artery, and interlobular artery. This is the correct sequence of blood vessels that carry oxygenated blood to the renal cortex, allowing for the filtration of waste products and reabsorption of water and nutrients in the kidneys.

Explanation

The correct answer traces the blood flow from the renal artery into the renal cortex in the following order: segmental artery, interlobar artery, arcuate artery, and interlobular artery. This is the correct sequence of blood vessels that carry oxygenated blood to the renal cortex, allowing for the filtration of waste products and reabsorption of water and nutrients in the kidneys.

4. In the nephron, the fluid that immediately precedes urine is known as

Plasma.

Glomerular filtrate.

Tubular fluid.

Renal filtrate.

Medullary filtrate.

The correct answer is tubular fluid. In the nephron, the fluid that immediately precedes urine is known as tubular fluid. This fluid is formed by the filtration of blood in the glomerulus and then modified through reabsorption and secretion as it passes through the renal tubules. Eventually, the tubular fluid will be further concentrated and transformed into urine as it moves through the collecting ducts and into the renal pelvis.

Explanation

The correct answer is tubular fluid. In the nephron, the fluid that immediately precedes urine is known as tubular fluid. This fluid is formed by the filtration of blood in the glomerulus and then modified through reabsorption and secretion as it passes through the renal tubules. Eventually, the tubular fluid will be further concentrated and transformed into urine as it moves through the collecting ducts and into the renal pelvis.

5. Normal urine from a healthy person can be expected to contain all of the following except

Creatinine

Urobilin

Glucose

Ammonia

Magnesium

Normal urine from a healthy person does not typically contain glucose. Glucose is usually reabsorbed by the kidneys and returned to the bloodstream. The presence of glucose in urine can indicate a condition such as diabetes or kidney disease. Therefore, it is expected that normal urine from a healthy person would not contain glucose.

Explanation

Normal urine from a healthy person does not typically contain glucose. Glucose is usually reabsorbed by the kidneys and returned to the bloodstream. The presence of glucose in urine can indicate a condition such as diabetes or kidney disease. Therefore, it is expected that normal urine from a healthy person would not contain glucose.

6. Which of the following is not found in the ureter?

Adventitia

Two layers of smooth muscle

Three layers of smooth muscle

Transitional epithelium

Skeletal muscle

The ureter is a tube that carries urine from the kidneys to the bladder. It is composed of three layers of smooth muscle, known as the muscularis layer, which helps propel urine through the ureter. The adventitia is the outermost layer of the ureter, providing support and protection. Transitional epithelium is the innermost layer of the ureter, which allows for stretching and expansion. Skeletal muscle is not found in the ureter, as it is not needed for the function of transporting urine.

Explanation

The ureter is a tube that carries urine from the kidneys to the bladder. It is composed of three layers of smooth muscle, known as the muscularis layer, which helps propel urine through the ureter. The adventitia is the outermost layer of the ureter, providing support and protection. Transitional epithelium is the innermost layer of the ureter, which allows for stretching and expansion. Skeletal muscle is not found in the ureter, as it is not needed for the function of transporting urine.

7. The enterogastric reflex serves to

Relax the stomach in preparation for swallowed food.

Stimulate acid and enzyme secretion when food enters the stomach.

Stimulate intestinal motility when there is food in the stomach.

Inhibit gastric motility when there is chyme in the small intestine.

Relax the ileocecal valve when chyme is on its way to the colon.

The enterogastric reflex is a neural reflex that inhibits gastric motility when there is chyme (partially digested food) in the small intestine. This reflex helps to slow down the emptying of the stomach and allows for proper digestion and absorption of nutrients in the small intestine.

Explanation

The enterogastric reflex is a neural reflex that inhibits gastric motility when there is chyme (partially digested food) in the small intestine. This reflex helps to slow down the emptying of the stomach and allows for proper digestion and absorption of nutrients in the small intestine.

8. In a healthy kidney, very little ___ is filtered by the glomerulus.

Amino acids

Electrolytes

Glucose

Vitamins

Protein

In a healthy kidney, the glomerulus acts as a filtration unit and is responsible for filtering waste products and excess substances from the blood. Protein is a large molecule that is not normally filtered by the glomerulus, as it is essential for various bodily functions and is usually reabsorbed by the kidney. Therefore, very little protein is filtered by the glomerulus in a healthy kidney.

Explanation

In a healthy kidney, the glomerulus acts as a filtration unit and is responsible for filtering waste products and excess substances from the blood. Protein is a large molecule that is not normally filtered by the glomerulus, as it is essential for various bodily functions and is usually reabsorbed by the kidney. Therefore, very little protein is filtered by the glomerulus in a healthy kidney.

9. Assuming all other values are normal, calculate the net filtration pressure in a patient with a drop in capsular hydrostatic pressure to 8 mmHg.

10 mm Hg out

20 mm Hg out

30 mm Hg out

40 mm Hg out

50 mm Hg out

A drop in capsular hydrostatic pressure to 8 mmHg would decrease the net filtration pressure. The net filtration pressure is calculated by subtracting the sum of the opposing forces (capsular hydrostatic pressure and blood colloid osmotic pressure) from the glomerular hydrostatic pressure. Since the question states that all other values are normal and does not provide any information about the other pressures, we can assume they remain constant. Therefore, the net filtration pressure would be 20 mmHg out, as it is the only value that is lower than the initial glomerular hydrostatic pressure of 30 mmHg.

Explanation

A drop in capsular hydrostatic pressure to 8 mmHg would decrease the net filtration pressure. The net filtration pressure is calculated by subtracting the sum of the opposing forces (capsular hydrostatic pressure and blood colloid osmotic pressure) from the glomerular hydrostatic pressure. Since the question states that all other values are normal and does not provide any information about the other pressures, we can assume they remain constant. Therefore, the net filtration pressure would be 20 mmHg out, as it is the only value that is lower than the initial glomerular hydrostatic pressure of 30 mmHg.

10. Why is breast milk superior to cow's milk for an infant?

Cow's milk provides fewer calories per mL.

Cow's milk provides less calcium per mL.

Cow's milk provides less phosphorous per mL.

Cow's milk has too much protein and minerals in it.

It is a myth; cow's milk is equal in quality to breast milk.

Breast milk is considered superior to cow's milk for infants because cow's milk contains excessive amounts of protein and minerals, which can be difficult for an infant's immature digestive system to handle. This can lead to digestive issues and potential kidney damage. Breast milk, on the other hand, is specifically tailored to meet the nutritional needs of infants, providing the right balance of nutrients, including protein and minerals, in a form that is easily digestible and absorbable.

Explanation

Breast milk is considered superior to cow's milk for infants because cow's milk contains excessive amounts of protein and minerals, which can be difficult for an infant's immature digestive system to handle. This can lead to digestive issues and potential kidney damage. Breast milk, on the other hand, is specifically tailored to meet the nutritional needs of infants, providing the right balance of nutrients, including protein and minerals, in a form that is easily digestible and absorbable.

11. The urine is most likely to be hypotonic when

The body's water volume is high.

The body's pH is low.

The output of antidiuretic hormone is high.

The output of natriuretic peptides is high.

A person is lost and deprived of drinking water.

When the body's water volume is high, it means there is an excess of water in the body. This leads to a decrease in the concentration of solutes in the urine, making it hypotonic. In a hypotonic urine, the concentration of solutes is lower compared to the concentration in the blood. This occurs because the excess water is not being reabsorbed by the kidneys, resulting in a larger volume of urine with a lower concentration of solutes.

Explanation

When the body's water volume is high, it means there is an excess of water in the body. This leads to a decrease in the concentration of solutes in the urine, making it hypotonic. In a hypotonic urine, the concentration of solutes is lower compared to the concentration in the blood. This occurs because the excess water is not being reabsorbed by the kidneys, resulting in a larger volume of urine with a lower concentration of solutes.

12. Amino acids and monosaccharides are absorbed in the ____________, and fatty acids are absorbed in the _______________.

Small intestine; large intestine

Small intestine; liver

Stomach; small intestine

Stomach; large intestine

Small intestine; small intestine too

Amino acids and monosaccharides are primarily absorbed in the small intestine. However, it is worth noting that a small amount of absorption of these molecules can also occur in the small intestine itself. This is because the small intestine has a large surface area due to the presence of villi and microvilli, which increases the absorption capacity. On the other hand, fatty acids are primarily absorbed in the small intestine as well, through a process called emulsification and subsequent formation of micelles. The large intestine mainly absorbs water and electrolytes, rather than nutrients like amino acids, monosaccharides, or fatty acids.

Explanation

Amino acids and monosaccharides are primarily absorbed in the small intestine. However, it is worth noting that a small amount of absorption of these molecules can also occur in the small intestine itself. This is because the small intestine has a large surface area due to the presence of villi and microvilli, which increases the absorption capacity. On the other hand, fatty acids are primarily absorbed in the small intestine as well, through a process called emulsification and subsequent formation of micelles. The large intestine mainly absorbs water and electrolytes, rather than nutrients like amino acids, monosaccharides, or fatty acids.

13. The migrating motor complex

Milks the chyme toward the colon.

Allows a bolus to move down the esophagus.

Churns and mixes residue in the descending colon.

Churns and mixes a bolus with gastric juices.

Propels pancreatic juice down the pancreatic duct.

The migrating motor complex refers to a series of contractions that occur in the gastrointestinal tract during fasting periods. These contractions help to propel any remaining food particles, known as chyme, from the stomach towards the colon. This process ensures that the chyme continues to move through the digestive system and prevents it from staying in one place for too long. Therefore, the correct answer is that the migrating motor complex milks the chyme toward the colon.

Explanation

The migrating motor complex refers to a series of contractions that occur in the gastrointestinal tract during fasting periods. These contractions help to propel any remaining food particles, known as chyme, from the stomach towards the colon. This process ensures that the chyme continues to move through the digestive system and prevents it from staying in one place for too long. Therefore, the correct answer is that the migrating motor complex milks the chyme toward the colon.

14.

Normally the systemic arterial blood has a Po₂ of _____ mm Hg, a Pco₂ of _____ mm Hg, and a pH of _____.

40; 95; 7.4

95; 40; 7.4

7.4; 40; 95

95; 7.4; 40

40; 7.4; 95

not-available-via-ai

Explanation

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15. A patient enters a hospital after a motorcycle accident. He complains of mid-back pain. X-rays reveal both rib and pelvic fractures. His emergency room examination includes urinalysis. Which of the following findings from the urinalysis would most likely suggest trauma to the kidneys from the accident, but not to the urinary bladder?

Pyuria

Hematuria

Albuminuria

Uremia

Phenylketonuria

Albuminuria is the presence of albumin in the urine, which is a protein normally found in the blood. In the context of trauma to the kidneys, albuminuria suggests damage to the glomerular filtration barrier, allowing the protein to leak into the urine. This finding is specific to kidney injury and not commonly associated with trauma to the urinary bladder. Pyuria refers to the presence of pus in the urine and can be seen in both kidney and bladder trauma. Hematuria, the presence of blood in the urine, can also be seen in both kidney and bladder trauma. Uremia refers to the buildup of waste products in the blood due to kidney dysfunction and is not specific to trauma. Phenylketonuria is a genetic disorder and not related to trauma.

Explanation

Albuminuria is the presence of albumin in the urine, which is a protein normally found in the blood. In the context of trauma to the kidneys, albuminuria suggests damage to the glomerular filtration barrier, allowing the protein to leak into the urine. This finding is specific to kidney injury and not commonly associated with trauma to the urinary bladder. Pyuria refers to the presence of pus in the urine and can be seen in both kidney and bladder trauma. Hematuria, the presence of blood in the urine, can also be seen in both kidney and bladder trauma. Uremia refers to the buildup of waste products in the blood due to kidney dysfunction and is not specific to trauma. Phenylketonuria is a genetic disorder and not related to trauma.

16. All of the following are composed of cuboidal epithelium with the exception of

The thin segment of the nephron loop.

The thick segment of the nephron loop.

The collecting duct.

The distal convoluted tubule.

The thin segment of the nephron loop is composed of simple squamous epithelium, not cuboidal epithelium like the other structures mentioned.

Explanation

The thin segment of the nephron loop is composed of simple squamous epithelium, not cuboidal epithelium like the other structures mentioned.

17. In response to a drop in overall blood pressure, ___ stimulates constriction of the glomerular inlet and even greater constriction of the outlet.

Azotemia

Sodium chloride

Parathyroid hormone

Aldosterone

Angiotensin II

In response to a drop in overall blood pressure, angiotensin II stimulates constriction of the glomerular inlet and even greater constriction of the outlet. Angiotensin II is a hormone that is released by the kidneys in response to low blood pressure. It acts on the blood vessels to constrict them, which helps to increase blood pressure. In the case of the glomerular inlet and outlet, angiotensin II constricts them even more to regulate the flow of blood and maintain proper filtration in the kidneys.

Explanation

In response to a drop in overall blood pressure, angiotensin II stimulates constriction of the glomerular inlet and even greater constriction of the outlet. Angiotensin II is a hormone that is released by the kidneys in response to low blood pressure. It acts on the blood vessels to constrict them, which helps to increase blood pressure. In the case of the glomerular inlet and outlet, angiotensin II constricts them even more to regulate the flow of blood and maintain proper filtration in the kidneys.

18. A lung disease marked by abnormally few but large alveoli is

Cor pulmonale.

Pulmonary hemosiderosis.

Emphysema.

Atelectasis.

Collapsed lung.

Emphysema is a lung disease characterized by the destruction of the alveoli, resulting in abnormally large air sacs with reduced surface area for gas exchange. This leads to difficulty in breathing and decreased oxygenation of the blood. Cor pulmonale refers to right-sided heart failure caused by lung disease, pulmonary hemosiderosis is a condition where iron accumulates in the lungs, atelectasis is the collapse of a lung or part of it, and a collapsed lung refers to the partial or complete collapse of the lung due to air or gas accumulation outside the lung or within the lung itself.

Explanation

Emphysema is a lung disease characterized by the destruction of the alveoli, resulting in abnormally large air sacs with reduced surface area for gas exchange. This leads to difficulty in breathing and decreased oxygenation of the blood. Cor pulmonale refers to right-sided heart failure caused by lung disease, pulmonary hemosiderosis is a condition where iron accumulates in the lungs, atelectasis is the collapse of a lung or part of it, and a collapsed lung refers to the partial or complete collapse of the lung due to air or gas accumulation outside the lung or within the lung itself.

19. Proximal convoluted tubules are responsible for reabsorbing all of the following except

Potassium.

Sodium chloride.

Hydrogen ions.

Urea.

Water.

The proximal convoluted tubules in the kidneys are responsible for reabsorbing various substances from the filtrate back into the bloodstream. These substances include sodium chloride, potassium, urea, and water. However, hydrogen ions are not reabsorbed by the proximal convoluted tubules. Instead, they are secreted into the tubules to help regulate the body's pH levels.

Explanation

The proximal convoluted tubules in the kidneys are responsible for reabsorbing various substances from the filtrate back into the bloodstream. These substances include sodium chloride, potassium, urea, and water. However, hydrogen ions are not reabsorbed by the proximal convoluted tubules. Instead, they are secreted into the tubules to help regulate the body's pH levels.

20. Which of the following is a direct result of antidiuretic hormone?

Decreased urine volume

Decreased urine molarity

Increased urine volume

Increased urine salinity

Increased urine acidity

Antidiuretic hormone (ADH) is released by the pituitary gland and its main function is to regulate water balance in the body. When ADH is released, it acts on the kidneys to increase water reabsorption, leading to decreased urine volume. Therefore, the correct answer is decreased urine volume.

Explanation

Antidiuretic hormone (ADH) is released by the pituitary gland and its main function is to regulate water balance in the body. When ADH is released, it acts on the kidneys to increase water reabsorption, leading to decreased urine volume. Therefore, the correct answer is decreased urine volume.

21. Which is not a function of the kidneys?

They regulate osmolarity of the body fluids

They fight osteoporosis by synthesizing vitamin D.

They help control blood pressure.

They release waste into the bloodstream.

They indirectly increase oxyhemoglobin.

The kidneys do not release waste into the bloodstream. Instead, they filter waste products from the bloodstream and excrete them in the form of urine. This is one of the main functions of the kidneys, along with regulating osmolarity of body fluids, synthesizing vitamin D, helping control blood pressure, and indirectly increasing oxyhemoglobin levels.

Explanation

The kidneys do not release waste into the bloodstream. Instead, they filter waste products from the bloodstream and excrete them in the form of urine. This is one of the main functions of the kidneys, along with regulating osmolarity of body fluids, synthesizing vitamin D, helping control blood pressure, and indirectly increasing oxyhemoglobin levels.

22. Which renal structure is responsible for producing hypertonic urine by reabsorbing water while allowing metabolic wastes and NaCl to pass through?

Glomerulus

Proximal convoluted tubule

Distal convoluted tubule

Collecting duct

Nephron loop

The collecting duct is responsible for producing hypertonic urine by reabsorbing water while allowing metabolic wastes and NaCl to pass through. This structure plays a crucial role in concentrating the urine by reabsorbing water back into the bloodstream and allowing the passage of solutes such as metabolic wastes and NaCl. This selective reabsorption helps in maintaining the body's water and electrolyte balance. The other structures mentioned, such as the glomerulus, proximal convoluted tubule, distal convoluted tubule, and nephron loop, also play important roles in the renal system but are not primarily responsible for producing hypertonic urine.

Explanation

The collecting duct is responsible for producing hypertonic urine by reabsorbing water while allowing metabolic wastes and NaCl to pass through. This structure plays a crucial role in concentrating the urine by reabsorbing water back into the bloodstream and allowing the passage of solutes such as metabolic wastes and NaCl. This selective reabsorption helps in maintaining the body's water and electrolyte balance. The other structures mentioned, such as the glomerulus, proximal convoluted tubule, distal convoluted tubule, and nephron loop, also play important roles in the renal system but are not primarily responsible for producing hypertonic urine.

23. Which of these is the site of contact digestion?

Gastric pits

Surface of the gastric mucosa

Intestinal crypts

Brush border of the small intestine

Cytoplasm in the cells of the small intestine

The brush border of the small intestine is the site of contact digestion. The brush border refers to the microvilli on the surface of the intestinal epithelial cells. These microvilli greatly increase the surface area available for digestion and absorption of nutrients. Enzymes located on the brush border, such as sucrase, lactase, and maltase, break down disaccharides into monosaccharides, which can then be absorbed by the cells. Therefore, the brush border plays a crucial role in the digestion of carbohydrates in the small intestine.

Explanation

The brush border of the small intestine is the site of contact digestion. The brush border refers to the microvilli on the surface of the intestinal epithelial cells. These microvilli greatly increase the surface area available for digestion and absorption of nutrients. Enzymes located on the brush border, such as sucrase, lactase, and maltase, break down disaccharides into monosaccharides, which can then be absorbed by the cells. Therefore, the brush border plays a crucial role in the digestion of carbohydrates in the small intestine.

24. The small intestine has a very large absorptive surface associated with all these structures except

Circular folds (plicae circulares).

Intestinal length.

Microvilli.

Villi.

Rugae

The small intestine has a very large absorptive surface due to the presence of circular folds (plicae circulares), microvilli, and villi. These structures increase the surface area available for absorption of nutrients. However, rugae are not associated with the absorptive surface of the small intestine. Rugae are found in the stomach and urinary bladder, and they allow for expansion and contraction of these organs.

Explanation

The small intestine has a very large absorptive surface due to the presence of circular folds (plicae circulares), microvilli, and villi. These structures increase the surface area available for absorption of nutrients. However, rugae are not associated with the absorptive surface of the small intestine. Rugae are found in the stomach and urinary bladder, and they allow for expansion and contraction of these organs.

25. _____________ break(s) down _______________.

Lactase; glucose

Peptidases; proteins

Lipases; micelles

Lactose; lactase

Nucleases; nucleotides

Peptidases are enzymes that break down proteins into smaller peptides or amino acids. Therefore, the correct answer is "Peptidases; proteins" because peptidases break down proteins.

Explanation

Peptidases are enzymes that break down proteins into smaller peptides or amino acids. Therefore, the correct answer is "Peptidases; proteins" because peptidases break down proteins.

26. Each of the following lists some of the tissue layers of the digestive tract. Which one has them in correct order from lumen to external surface?

Lamina propria, muscularis mucosae, submucosa, muscularis externa, serosa

Serosa, lamina propria, submucosa, muscularis mucosae, muscularis externa

Mucosa, submucosa, muscularis mucosae, muscularis externa, lamina propria

Mucosa, muscularis mucosae, submucosa, muscularis externa, lamina propria

Mucosa, submucosa, muscularis externa, lamina propria, serosa

The correct answer is lamina propria, muscularis mucosae, submucosa, muscularis externa, serosa. This is the correct order of the tissue layers from the lumen (innermost) to the external surface (outermost) of the digestive tract. The lamina propria is a layer of connective tissue that lies just beneath the epithelial lining of the mucosa. The muscularis mucosae is a thin layer of smooth muscle that helps to move and mix the contents of the digestive tract. The submucosa is a layer of connective tissue that contains blood vessels, nerves, and glands. The muscularis externa is a layer of smooth muscle that helps to propel food through the digestive tract. The serosa is the outermost layer of the digestive tract, which provides protection and support.

Explanation

The correct answer is lamina propria, muscularis mucosae, submucosa, muscularis externa, serosa. This is the correct order of the tissue layers from the lumen (innermost) to the external surface (outermost) of the digestive tract. The lamina propria is a layer of connective tissue that lies just beneath the epithelial lining of the mucosa. The muscularis mucosae is a thin layer of smooth muscle that helps to move and mix the contents of the digestive tract. The submucosa is a layer of connective tissue that contains blood vessels, nerves, and glands. The muscularis externa is a layer of smooth muscle that helps to propel food through the digestive tract. The serosa is the outermost layer of the digestive tract, which provides protection and support.

27. Atrial natriuretic peptide reduces blood volume and pressure by all of the following means except

Increasing glomerular filtration rate.

Inhibiting renin and aldosterone secretion.

Inhibiting the action of ADH on the kidney.

Inhibiting NaCl reabsorption by the collecting duct.

Preventing sodium loss in the urine.

Atrial natriuretic peptide (ANP) is a hormone released by the heart in response to increased blood volume and pressure. It acts to reduce blood volume and pressure by various mechanisms. ANP inhibits renin and aldosterone secretion, which leads to decreased reabsorption of sodium and water in the kidneys. It also inhibits the action of antidiuretic hormone (ADH) on the kidney, which reduces water reabsorption. ANP inhibits NaCl reabsorption by the collecting duct, further promoting water and sodium excretion. However, preventing sodium loss in the urine would not contribute to reducing blood volume and pressure, therefore it is the exception in this case.

Explanation

Atrial natriuretic peptide (ANP) is a hormone released by the heart in response to increased blood volume and pressure. It acts to reduce blood volume and pressure by various mechanisms. ANP inhibits renin and aldosterone secretion, which leads to decreased reabsorption of sodium and water in the kidneys. It also inhibits the action of antidiuretic hormone (ADH) on the kidney, which reduces water reabsorption. ANP inhibits NaCl reabsorption by the collecting duct, further promoting water and sodium excretion. However, preventing sodium loss in the urine would not contribute to reducing blood volume and pressure, therefore it is the exception in this case.

28. Acid reflux into the esophagus ("heartburn") is normally prevented by

Pharyngeal constrictors.

The upper esophageal sphincter.

The lower esophageal sphincter (LES).

Esophageal glands.

Pharyngeal and buccal sphincters.

The lower esophageal sphincter (LES) is responsible for preventing acid reflux into the esophagus. This sphincter is located at the junction between the esophagus and the stomach, and its main function is to close off the opening between these two organs to prevent stomach acid from flowing back into the esophagus. When the LES is functioning properly, it acts as a barrier to keep stomach contents in the stomach. However, if the LES weakens or relaxes abnormally, acid can escape and cause heartburn or acid reflux.

Explanation

The lower esophageal sphincter (LES) is responsible for preventing acid reflux into the esophagus. This sphincter is located at the junction between the esophagus and the stomach, and its main function is to close off the opening between these two organs to prevent stomach acid from flowing back into the esophagus. When the LES is functioning properly, it acts as a barrier to keep stomach contents in the stomach. However, if the LES weakens or relaxes abnormally, acid can escape and cause heartburn or acid reflux.

29. The ______________ of the small intestine is/are similar to the _________________ of the stomach.

Villi; pyloric glands

Rugae; Peyer patches

Intestinal crypts; gastric pits

Goblet cells; parietal cells

Pyloric sphincter; ileocecal valve

The correct answer is intestinal crypts; gastric pits. The small intestine and stomach both have structures that aid in their respective functions. The intestinal crypts in the small intestine are responsible for producing digestive enzymes and absorbing nutrients from food. Similarly, the gastric pits in the stomach contain cells that secrete gastric juices, including hydrochloric acid and enzymes, to break down food. Both structures play a crucial role in the digestion and absorption of nutrients.

Explanation

The correct answer is intestinal crypts; gastric pits. The small intestine and stomach both have structures that aid in their respective functions. The intestinal crypts in the small intestine are responsible for producing digestive enzymes and absorbing nutrients from food. Similarly, the gastric pits in the stomach contain cells that secrete gastric juices, including hydrochloric acid and enzymes, to break down food. Both structures play a crucial role in the digestion and absorption of nutrients.

30. ____________ transport lipids to the surface of the intestinal absorptive cells, which process them into _________________.

Fat droplets; micelles

Fat droplets; chylomicrons

Micelles; fat globules

Micelles; chylomicrons

Fat globules; micelles

Micelles are small structures formed by the aggregation of lipids in the small intestine. They aid in the absorption of lipids by increasing their surface area for digestion by enzymes. Chylomicrons, on the other hand, are large lipoprotein particles that transport dietary lipids, such as triglycerides, from the intestinal cells into the lymphatic system and eventually into the bloodstream. Therefore, micelles transport lipids to the surface of the intestinal absorptive cells, which process them into chylomicrons.

Explanation

Micelles are small structures formed by the aggregation of lipids in the small intestine. They aid in the absorption of lipids by increasing their surface area for digestion by enzymes. Chylomicrons, on the other hand, are large lipoprotein particles that transport dietary lipids, such as triglycerides, from the intestinal cells into the lymphatic system and eventually into the bloodstream. Therefore, micelles transport lipids to the surface of the intestinal absorptive cells, which process them into chylomicrons.

31. The _______________ synthesizes bile acids by metabolizing ____________________.

Duodenum; neutral fats

Ileum; bilirubin

Gallbladder; cholesterol

Pancreas; bile salts

Liver; cholesterol

The liver synthesizes bile acids by metabolizing cholesterol.

Explanation

The liver synthesizes bile acids by metabolizing cholesterol.

32. Which of these correctly traces blood flow from the renal cortex to the renal vein?

Interlobular v. → interlobar v. → segmental v. → renal v.

Arcuate v. → interlobar v. → segmental v. → renal v.

Interlobar v. → interlobular v. → arcuate v. → renal v.

Segmental v. → arcuate v. → interlobar v. → renal v.

Interlobular v. → arcuate v. → interlobar v. → renal v.

The correct answer traces the blood flow correctly from the renal cortex to the renal vein. It starts with the interlobular veins, which drain blood from the renal cortex. The blood then flows into the arcuate veins, which are located at the boundary between the renal cortex and medulla. From there, it goes into the interlobar veins, which travel through the renal columns. Finally, the blood enters the renal vein, which carries it out of the kidney.

Explanation

The correct answer traces the blood flow correctly from the renal cortex to the renal vein. It starts with the interlobular veins, which drain blood from the renal cortex. The blood then flows into the arcuate veins, which are located at the boundary between the renal cortex and medulla. From there, it goes into the interlobar veins, which travel through the renal columns. Finally, the blood enters the renal vein, which carries it out of the kidney.

33. These nutrients are all absorbed without being digested except

Water.

Vitamins.

Proteins.

Minerals.

Cholesterol.

Proteins are the only nutrients that require digestion before they can be absorbed by the body. Digestion breaks down proteins into amino acids, which can then be absorbed into the bloodstream. In contrast, water, vitamins, minerals, and cholesterol do not require digestion and can be directly absorbed by the body.

Explanation

Proteins are the only nutrients that require digestion before they can be absorbed by the body. Digestion breaks down proteins into amino acids, which can then be absorbed into the bloodstream. In contrast, water, vitamins, minerals, and cholesterol do not require digestion and can be directly absorbed by the body.

34.

Vital capacity consists of

Inspiratory reserve volume + expiratory volume.

Inspiratory reserve volume + tidal volume.

Expiratory reserve volume + tidal volume.

Expiratory reserve volume + tidal volume + inspiratory reserve volume.

Respiratory volume + tidal volume.

Vital capacity is the maximum amount of air that can be forcibly exhaled after a maximum inhalation. It is calculated by adding the expiratory reserve volume (the amount of air that can still be exhaled after a normal exhalation) to the tidal volume (the amount of air inhaled and exhaled during normal breathing) and the inspiratory reserve volume (the amount of air that can still be inhaled after a normal inhalation). Therefore, the correct answer is expiratory reserve volume + tidal volume + inspiratory reserve volume.

Explanation

Vital capacity is the maximum amount of air that can be forcibly exhaled after a maximum inhalation. It is calculated by adding the expiratory reserve volume (the amount of air that can still be exhaled after a normal exhalation) to the tidal volume (the amount of air inhaled and exhaled during normal breathing) and the inspiratory reserve volume (the amount of air that can still be inhaled after a normal inhalation). Therefore, the correct answer is expiratory reserve volume + tidal volume + inspiratory reserve volume.

35.

Each hemoglobin molecule can transport up to _____ oxygen molecules.

1

2

3

4

5

Each hemoglobin molecule can transport up to 4 oxygen molecules.

Explanation

Each hemoglobin molecule can transport up to 4 oxygen molecules.

36. Total saturation of protein transporters for a given solute in the renal tubules would result in

Reabsorption of all the solute.

A renal clearance of zero.

Appearance of that solute in the urine.

Absence of that solute from the urine.

A net filtration pressure of 1.0.

When the protein transporters in the renal tubules are fully saturated with a given solute, it means that they are unable to reabsorb any more of that solute back into the bloodstream. This leads to the solute being unable to be reabsorbed and therefore appearing in the urine. So, the correct answer is the appearance of that solute in the urine.

Explanation

When the protein transporters in the renal tubules are fully saturated with a given solute, it means that they are unable to reabsorb any more of that solute back into the bloodstream. This leads to the solute being unable to be reabsorbed and therefore appearing in the urine. So, the correct answer is the appearance of that solute in the urine.

37. Which of the following would lead to anemic hypoxia?

Sickle-cell disease

Emphysema

Squamous-cell carcinoma

Asthma

Atelectasis

Anemic hypoxia occurs when there is a decrease in the oxygen-carrying capacity of the blood. Sickle-cell disease is a genetic disorder that causes red blood cells to become abnormally shaped and rigid. These abnormal cells can block blood vessels, leading to reduced oxygen delivery to tissues and organs. This reduction in oxygen-carrying capacity can result in anemic hypoxia. Emphysema, squamous-cell carcinoma, asthma, and atelectasis may cause other types of hypoxia, but not specifically anemic hypoxia.

Explanation

Anemic hypoxia occurs when there is a decrease in the oxygen-carrying capacity of the blood. Sickle-cell disease is a genetic disorder that causes red blood cells to become abnormally shaped and rigid. These abnormal cells can block blood vessels, leading to reduced oxygen delivery to tissues and organs. This reduction in oxygen-carrying capacity can result in anemic hypoxia. Emphysema, squamous-cell carcinoma, asthma, and atelectasis may cause other types of hypoxia, but not specifically anemic hypoxia.

38. Men have only one ____________ but have two of all the rest of these.

Bulbourethral gland(s)

Prostate gland(s)

Ejaculatory duct(s)

Seminal vesicle(s)

Corpus(ora) cavernosum(a)

Men have only one prostate gland but have two of all the rest of these. This is because the prostate gland is a single gland located just below the bladder, while the other options listed (bulbourethral glands, ejaculatory ducts, seminal vesicles, corpus cavernosum) are all paired structures found in the male reproductive system. The prostate gland plays a crucial role in producing and secreting seminal fluid, which helps nourish and transport sperm during ejaculation.

Explanation

Men have only one prostate gland but have two of all the rest of these. This is because the prostate gland is a single gland located just below the bladder, while the other options listed (bulbourethral glands, ejaculatory ducts, seminal vesicles, corpus cavernosum) are all paired structures found in the male reproductive system. The prostate gland plays a crucial role in producing and secreting seminal fluid, which helps nourish and transport sperm during ejaculation.

39. Scuba divers breathe a nitrogen-oxygen mixture rather than pure compressed oxygen in order to avoid

The bends.

Oxygen toxicity.

Rapture of the deep.

Caisson disease.

Hypoxemic hypoxia.

Scuba divers breathe a nitrogen-oxygen mixture rather than pure compressed oxygen in order to avoid oxygen toxicity. Breathing pure oxygen at high pressures and for extended periods can lead to oxygen toxicity, which can cause seizures, lung damage, and other serious health issues. By diluting the oxygen with nitrogen, scuba divers can reduce the risk of oxygen toxicity and safely explore underwater environments.

Explanation

Scuba divers breathe a nitrogen-oxygen mixture rather than pure compressed oxygen in order to avoid oxygen toxicity. Breathing pure oxygen at high pressures and for extended periods can lead to oxygen toxicity, which can cause seizures, lung damage, and other serious health issues. By diluting the oxygen with nitrogen, scuba divers can reduce the risk of oxygen toxicity and safely explore underwater environments.

40. _____________ stimulates the interstitial cells of the testes to secrete __________.

Gonadotropin-releasing hormone (GnRH); LH

Follicle-stimulating hormone (FSH); androgen-binding protein (ABP)

Luteinizing hormone (LH); androgen-binding protein (ABP)

Luteinizing hormone (LH); testosterone

Luteinizing hormone (LH); estrogen

Luteinizing hormone (LH) stimulates the interstitial cells of the testes to secrete testosterone.

Explanation

Luteinizing hormone (LH) stimulates the interstitial cells of the testes to secrete testosterone.

41. Chemical digestion breaks down ____________ into _____________.

Proteins; nucleotides

Amino acids; proteins

Polysaccharides; amino acids

Nucleic acids; nucleotides

Fatty acids; cholesterol

Chemical digestion is the process in which large molecules are broken down into smaller molecules by the action of enzymes. In this case, chemical digestion breaks down nucleic acids into nucleotides. Nucleic acids are large molecules that contain genetic information, such as DNA and RNA. Nucleotides are the building blocks of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base. Therefore, the correct answer is "nucleic acids; nucleotides."

Explanation

Chemical digestion is the process in which large molecules are broken down into smaller molecules by the action of enzymes. In this case, chemical digestion breaks down nucleic acids into nucleotides. Nucleic acids are large molecules that contain genetic information, such as DNA and RNA. Nucleotides are the building blocks of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base. Therefore, the correct answer is "nucleic acids; nucleotides."

42. Hypocalcemia stimulates

A decrease in aldosterone production.

Secretion of parathyroid hormone.

Secretion of renin.

An increase in blood urea nitrogen.

Vasoconstriction of the afferent arterioles.

Hypocalcemia refers to low levels of calcium in the blood. Parathyroid hormone (PTH) is responsible for regulating calcium levels in the body. When calcium levels are low, the parathyroid glands secrete more PTH, which stimulates the release of calcium from bones, increases calcium absorption in the intestines, and reduces calcium excretion in the kidneys. Therefore, in the case of hypocalcemia, the correct answer is the secretion of parathyroid hormone.

Explanation

Hypocalcemia refers to low levels of calcium in the blood. Parathyroid hormone (PTH) is responsible for regulating calcium levels in the body. When calcium levels are low, the parathyroid glands secrete more PTH, which stimulates the release of calcium from bones, increases calcium absorption in the intestines, and reduces calcium excretion in the kidneys. Therefore, in the case of hypocalcemia, the correct answer is the secretion of parathyroid hormone.

43. Which two substances are most useful for determining a patient's glomerular filtration rate?

Insulin and glucose

Inulin and creatinine

Sodium and water

Albumin and inulin

Insulin and urea

Inulin and creatinine are the most useful substances for determining a patient's glomerular filtration rate. Inulin is a plant polysaccharide that is freely filtered by the glomerulus and is not reabsorbed or secreted by the renal tubules. Therefore, its clearance provides an accurate measure of the glomerular filtration rate. Creatinine is a waste product of muscle metabolism that is also freely filtered by the glomerulus and minimally reabsorbed by the renal tubules. Its clearance is commonly used as an estimate of the glomerular filtration rate in clinical practice.

Explanation

Inulin and creatinine are the most useful substances for determining a patient's glomerular filtration rate. Inulin is a plant polysaccharide that is freely filtered by the glomerulus and is not reabsorbed or secreted by the renal tubules. Therefore, its clearance provides an accurate measure of the glomerular filtration rate. Creatinine is a waste product of muscle metabolism that is also freely filtered by the glomerulus and minimally reabsorbed by the renal tubules. Its clearance is commonly used as an estimate of the glomerular filtration rate in clinical practice.

44. Pepsinogen is produced by ____________ and is activated by ___________.

Chief cells; carbonic anhydrase (CAH) secreted by parietal cells

Chief cells; hydrochloric acid (HCl) secreted by parietal cells

Parietal cells; hydrochloric acid (HCl) secreted by chief cells

Parietal cells; carbonic anhydrase (CAH) secreted by chief cells

Enteroendocrine cells; carbonic anhydrase (CAH) secreted by parietal cells

Pepsinogen, the inactive form of the enzyme pepsin, is produced by chief cells in the stomach. It is then activated into pepsin by hydrochloric acid (HCl) secreted by parietal cells. Therefore, the correct answer is "chief cells; hydrochloric acid (HCl) secreted by parietal cells."

Explanation

Pepsinogen, the inactive form of the enzyme pepsin, is produced by chief cells in the stomach. It is then activated into pepsin by hydrochloric acid (HCl) secreted by parietal cells. Therefore, the correct answer is "chief cells; hydrochloric acid (HCl) secreted by parietal cells."

45. Which of the following would reduce the glomerular filtration rate?

Vasoconstriction of the efferent arteriole

A drop in oncotic pressure

Vasodilation of the afferent arteriole

Vasoconstriction of the afferent arteriole

An increase in osmotic pressure in the glomerular capsule

Vasoconstriction of the afferent arteriole would reduce the glomerular filtration rate. The afferent arteriole supplies blood to the glomerulus, where filtration occurs. When the afferent arteriole constricts, it reduces the amount of blood flow into the glomerulus, thereby decreasing the glomerular filtration rate. This constriction decreases the pressure within the glomerulus, leading to a decrease in the filtration of waste products and excess fluids from the blood.

Explanation

Vasoconstriction of the afferent arteriole would reduce the glomerular filtration rate. The afferent arteriole supplies blood to the glomerulus, where filtration occurs. When the afferent arteriole constricts, it reduces the amount of blood flow into the glomerulus, thereby decreasing the glomerular filtration rate. This constriction decreases the pressure within the glomerulus, leading to a decrease in the filtration of waste products and excess fluids from the blood.

46. _____________ is associated with food stretching the stomach and activating myenteric and vagovagal reflexes, which in turn stimulate gastric secretions.

The cephalic phase

The gastric phase

The intestinal phase

The gastrointestinal phase

The mesenteric phase

The gastric phase is associated with food stretching the stomach and activating myenteric and vagovagal reflexes, which in turn stimulate gastric secretions. During this phase, the stomach releases gastrin, which stimulates the secretion of gastric acid and enzymes. This phase is primarily triggered by the presence of food in the stomach and helps to prepare the stomach for digestion and absorption of nutrients.

Explanation

The gastric phase is associated with food stretching the stomach and activating myenteric and vagovagal reflexes, which in turn stimulate gastric secretions. During this phase, the stomach releases gastrin, which stimulates the secretion of gastric acid and enzymes. This phase is primarily triggered by the presence of food in the stomach and helps to prepare the stomach for digestion and absorption of nutrients.

47. Why are several digestive enzymes secreted as zymogens?

Because this saves one step in their synthesis

Because gastric cells do not have the necessary enzymes for their synthesis

So they start digesting intracellular proteins of the gastric cells more quickly

So they act only in the stomach lumen and do not digest intracellular proteins

So they can start digesting dietary proteins more quickly

Several digestive enzymes are secreted as zymogens to ensure that they act only in the stomach lumen and do not digest intracellular proteins. Zymogens are inactive forms of enzymes that are converted into their active forms when needed. This prevents the enzymes from prematurely digesting intracellular proteins within the gastric cells themselves. By remaining inactive until they reach the stomach lumen, the enzymes can then start digesting dietary proteins more quickly and efficiently.

Explanation

Several digestive enzymes are secreted as zymogens to ensure that they act only in the stomach lumen and do not digest intracellular proteins. Zymogens are inactive forms of enzymes that are converted into their active forms when needed. This prevents the enzymes from prematurely digesting intracellular proteins within the gastric cells themselves. By remaining inactive until they reach the stomach lumen, the enzymes can then start digesting dietary proteins more quickly and efficiently.

48. Which of the following enzymes functions at the lowest pH?

Salivary amylase

Pancreatic amylase

Pepsin

Trypsin

Dipeptidase

Pepsin functions at the lowest pH because it is an enzyme found in the stomach, where the pH is highly acidic (around pH 1-2). Pepsin is responsible for breaking down proteins into smaller peptides, and its activity is optimal in this acidic environment. Salivary amylase and pancreatic amylase function at a slightly higher pH in the mouth and small intestine, respectively. Trypsin and dipeptidase also function at a higher pH in the small intestine. Therefore, pepsin is the enzyme that functions at the lowest pH.

Explanation

Pepsin functions at the lowest pH because it is an enzyme found in the stomach, where the pH is highly acidic (around pH 1-2). Pepsin is responsible for breaking down proteins into smaller peptides, and its activity is optimal in this acidic environment. Salivary amylase and pancreatic amylase function at a slightly higher pH in the mouth and small intestine, respectively. Trypsin and dipeptidase also function at a higher pH in the small intestine. Therefore, pepsin is the enzyme that functions at the lowest pH.

49. Because of the great deal of active transport that occurs here, the _________ of all the nephrons collectively account for about 6% of one's daily resting ATP and caloric consumption.

Proximal convoluted tubules

Distal convoluted tubules

Loops of Henle

Glomerul

Collecting ducts

The proximal convoluted tubules are responsible for a significant amount of active transport, which requires ATP and consumes calories. This active transport is necessary for reabsorbing important substances such as glucose, amino acids, and ions back into the bloodstream. Due to the high energy demand of active transport in the proximal convoluted tubules, it accounts for about 6% of one's daily resting ATP and caloric consumption.

Explanation

The proximal convoluted tubules are responsible for a significant amount of active transport, which requires ATP and consumes calories. This active transport is necessary for reabsorbing important substances such as glucose, amino acids, and ions back into the bloodstream. Due to the high energy demand of active transport in the proximal convoluted tubules, it accounts for about 6% of one's daily resting ATP and caloric consumption.

50. Each alveolus is surrounded by a basket of blood capillaries supplied by

The aorta.

The pulmonary artery.

The pulmonary vein.

The inferior vena cava.

The superior vena cava.

The correct answer is the pulmonary artery. The alveoli are tiny air sacs in the lungs where gas exchange occurs. The pulmonary artery carries deoxygenated blood from the heart to the lungs, where it branches into smaller blood vessels called capillaries. These capillaries surround the alveoli, allowing for the exchange of oxygen and carbon dioxide between the blood and the air in the lungs.

Explanation

The correct answer is the pulmonary artery. The alveoli are tiny air sacs in the lungs where gas exchange occurs. The pulmonary artery carries deoxygenated blood from the heart to the lungs, where it branches into smaller blood vessels called capillaries. These capillaries surround the alveoli, allowing for the exchange of oxygen and carbon dioxide between the blood and the air in the lungs.

51. In a healthy person, which of the following will have the greatest influence on resistance to pulmonary airflow?

Atmospheric pressure

Respiratory rate

Bronchiole diameter

Quantity of surfactant

The diaphragm

Bronchiole diameter will have the greatest influence on resistance to pulmonary airflow in a healthy person. The diameter of the bronchioles determines the amount of air that can pass through them. A narrower diameter will increase resistance to airflow, while a wider diameter will decrease resistance. Therefore, if the bronchioles are constricted or narrowed, it will result in increased resistance and difficulty in breathing. Conversely, if the bronchioles are dilated or wider, it will decrease resistance and facilitate easier airflow.

Explanation

Bronchiole diameter will have the greatest influence on resistance to pulmonary airflow in a healthy person. The diameter of the bronchioles determines the amount of air that can pass through them. A narrower diameter will increase resistance to airflow, while a wider diameter will decrease resistance. Therefore, if the bronchioles are constricted or narrowed, it will result in increased resistance and difficulty in breathing. Conversely, if the bronchioles are dilated or wider, it will decrease resistance and facilitate easier airflow.

52. Which of the following would slow down gas exchange between the blood and alveolar air?

An increase in membrane thickness

An increase in alveolar surface area

An increase in respiratory rate

A decrease in membrane thickness

A decrease in nitrogen solubility

An increase in membrane thickness would slow down gas exchange between the blood and alveolar air because it would create a longer distance for gases to diffuse across. Thicker membranes would impede the diffusion of oxygen and carbon dioxide, making it more difficult for these gases to move between the alveoli and the bloodstream. This would result in a slower rate of gas exchange and potentially lead to decreased oxygen uptake and increased carbon dioxide retention.

Explanation

An increase in membrane thickness would slow down gas exchange between the blood and alveolar air because it would create a longer distance for gases to diffuse across. Thicker membranes would impede the diffusion of oxygen and carbon dioxide, making it more difficult for these gases to move between the alveoli and the bloodstream. This would result in a slower rate of gas exchange and potentially lead to decreased oxygen uptake and increased carbon dioxide retention.

53. A hospital patient produces 4 mL/min of urine with a urea concentration of 8 mg/mL. Venous blood draw reveals urea concentration of 0.4 mg/mL. What is the percentage of cleared urea from glomerular filtrate?

40%

56

64%

72%

80%

The percentage of cleared urea from glomerular filtrate can be calculated using the formula: (urine concentration - blood concentration) / urine concentration * 100. In this case, the urine concentration is 8 mg/mL and the blood concentration is 0.4 mg/mL. Plugging these values into the formula, we get (8 - 0.4) / 8 * 100 = 7.6 / 8 * 100 = 0.95 * 100 = 95%. Therefore, the correct answer is 95%.

Explanation

The percentage of cleared urea from glomerular filtrate can be calculated using the formula: (urine concentration - blood concentration) / urine concentration * 100. In this case, the urine concentration is 8 mg/mL and the blood concentration is 0.4 mg/mL. Plugging these values into the formula, we get (8 - 0.4) / 8 * 100 = 7.6 / 8 * 100 = 0.95 * 100 = 95%. Therefore, the correct answer is 95%.

54. The buccal phase of swallowing is under _____________ control and the pharyngo-esophageal phase is ______________.

Central nervous system; also controlled by the central nervous system

Central nervous system; controlled by autonomic reflexes

Autonomic nervous system; controlled by autonomic reflexes

Voluntary; also voluntary

Involuntary; also involuntary

The buccal phase of swallowing, which involves the initial voluntary movement of food into the mouth, is under central nervous system control. On the other hand, the pharyngo-esophageal phase, which involves the involuntary movement of food through the pharynx and esophagus, is controlled by autonomic reflexes.

Explanation

The buccal phase of swallowing, which involves the initial voluntary movement of food into the mouth, is under central nervous system control. On the other hand, the pharyngo-esophageal phase, which involves the involuntary movement of food through the pharynx and esophagus, is controlled by autonomic reflexes.

55. Why would an enlarged prostate gland interfere with urination?

It inhibits urine production.

It develops calcified deposits that block the urethra.

It produces thicker prostatic secretions that block the urethra.

It inhibits the micturition reflex.

It compresses the urethra.

An enlarged prostate gland can interfere with urination because it compresses the urethra. The prostate gland surrounds the urethra, which is the tube that carries urine from the bladder out of the body. When the prostate gland becomes enlarged, it can put pressure on the urethra, making it more difficult for urine to pass through. This can lead to symptoms such as a weak urine stream, difficulty starting or stopping urination, and the feeling of incomplete emptying of the bladder.

Explanation

An enlarged prostate gland can interfere with urination because it compresses the urethra. The prostate gland surrounds the urethra, which is the tube that carries urine from the bladder out of the body. When the prostate gland becomes enlarged, it can put pressure on the urethra, making it more difficult for urine to pass through. This can lead to symptoms such as a weak urine stream, difficulty starting or stopping urination, and the feeling of incomplete emptying of the bladder.

56. The ______________ has/have no androgen receptors and do/does not respond to it.

Germ cells

Muscular tissue

Sustentacular cells

Hypothalamus

Pituitary gland

Germ cells are the cells that give rise to sperm and eggs. These cells do not have androgen receptors, which are the receptors that bind to and respond to androgen hormones such as testosterone. Therefore, germ cells do not respond to androgen hormones.

Explanation

Germ cells are the cells that give rise to sperm and eggs. These cells do not have androgen receptors, which are the receptors that bind to and respond to androgen hormones such as testosterone. Therefore, germ cells do not respond to androgen hormones.

57. At the end of meiosis I there are ____________, whereas at the end of meiosis II there is/are _____________.

Two diploid cells; one diploid cell

Two diploid cells; one haploid cell

Two diploid cells; four haploid cells

Two haploid cells; four haploid cells

Two haploid cells; one diploid cell

At the end of meiosis I, there are two haploid cells formed. This is because during meiosis I, the homologous chromosomes separate, resulting in the division of the diploid cell into two haploid cells. At the end of meiosis II, there are four haploid cells formed. This is because during meiosis II, the sister chromatids separate, resulting in each haploid cell dividing into two, giving rise to a total of four haploid cells.

Explanation

At the end of meiosis I, there are two haploid cells formed. This is because during meiosis I, the homologous chromosomes separate, resulting in the division of the diploid cell into two haploid cells. At the end of meiosis II, there are four haploid cells formed. This is because during meiosis II, the sister chromatids separate, resulting in each haploid cell dividing into two, giving rise to a total of four haploid cells.

58.

Among its other purposes, the Valsalva maneuver is used

To aid in defecation and urination.

As part of the procedure for giving CPR to a person in respiratory arrest.

To ventilate the lungs during eupnea.

To expel more than the usual tidal volume from the lungs.

To clear carbon monoxide from the body and replace it with oxygen.

The Valsalva maneuver is used to aid in defecation and urination. This maneuver involves closing the glottis and contracting the muscles of the abdomen and diaphragm, which increases intra-abdominal pressure. This increased pressure can help to push stool and urine out of the body.

Explanation

The Valsalva maneuver is used to aid in defecation and urination. This maneuver involves closing the glottis and contracting the muscles of the abdomen and diaphragm, which increases intra-abdominal pressure. This increased pressure can help to push stool and urine out of the body.

59. Sildenafil (Viagra) prolongs erection by

Activating nitric oxide (NO) production.

Inactivating guanylate cyclase.

Stimulating production of cGMP.

Inhibiting degradation of cGMP.

Inhibiting nitric oxide (NO) production.

Sildenafil (Viagra) prolongs erection by inhibiting degradation of cGMP. This is because cGMP is responsible for relaxing the smooth muscles in the penis, allowing blood to flow in and causing an erection. Normally, cGMP is broken down by an enzyme called phosphodiesterase type 5 (PDE5). Sildenafil inhibits the action of PDE5, preventing the degradation of cGMP and maintaining its levels in the penis. This leads to prolonged vasodilation and an extended erection.

Explanation

Sildenafil (Viagra) prolongs erection by inhibiting degradation of cGMP. This is because cGMP is responsible for relaxing the smooth muscles in the penis, allowing blood to flow in and causing an erection. Normally, cGMP is broken down by an enzyme called phosphodiesterase type 5 (PDE5). Sildenafil inhibits the action of PDE5, preventing the degradation of cGMP and maintaining its levels in the penis. This leads to prolonged vasodilation and an extended erection.

60. Aldosterone acts on

The proximal convoluted tubule.

The medullary portion of the collecting duct.

The descending limb of the nephron loop.

The distal convoluted tubule.

The glomerulus.

Aldosterone acts on the distal convoluted tubule. The distal convoluted tubule is the part of the nephron where reabsorption of sodium ions and water occurs. Aldosterone increases the reabsorption of sodium ions and the secretion of potassium ions in the distal convoluted tubule, which helps regulate blood pressure and electrolyte balance. This hormone is produced by the adrenal glands and is released in response to low blood pressure or low sodium levels in the blood.

Explanation

Aldosterone acts on the distal convoluted tubule. The distal convoluted tubule is the part of the nephron where reabsorption of sodium ions and water occurs. Aldosterone increases the reabsorption of sodium ions and the secretion of potassium ions in the distal convoluted tubule, which helps regulate blood pressure and electrolyte balance. This hormone is produced by the adrenal glands and is released in response to low blood pressure or low sodium levels in the blood.

61. The surface of the tongue is covered with ____________ stratified squamous epithelium, and has bumps called __________________, site of taste buds.

Keratinized; lingual papillae

Keratinized; lingual frenulum

Nonkeratinized; lingual papillae

Nonkeratinized; tonsils

Nonkeratinized; vallate papillae

The surface of the tongue is covered with nonkeratinized stratified squamous epithelium, which means that the cells on the surface of the tongue do not have a layer of keratin. The bumps on the tongue are called lingual papillae, which are the site of taste buds.

Explanation

The surface of the tongue is covered with nonkeratinized stratified squamous epithelium, which means that the cells on the surface of the tongue do not have a layer of keratin. The bumps on the tongue are called lingual papillae, which are the site of taste buds.

62. Creatinine has a renal clearance of 140 mL/min due to the fact that

It is absorbed by the loop of Henle.

It is secreted by the glomerulus.

It is absorbed by the renal tubules.

It is secreted by the renal tubules.

It is produced in the pulmonary tissue.

Creatinine is a waste product produced by muscles and filtered by the glomerulus in the kidneys. However, a small amount of creatinine is also actively secreted by the renal tubules into the urine. This secretion process helps to eliminate creatinine from the body more efficiently. Therefore, the correct answer is that creatinine is secreted by the renal tubules.

Explanation

Creatinine is a waste product produced by muscles and filtered by the glomerulus in the kidneys. However, a small amount of creatinine is also actively secreted by the renal tubules into the urine. This secretion process helps to eliminate creatinine from the body more efficiently. Therefore, the correct answer is that creatinine is secreted by the renal tubules.

63. The muscle tone of the ________________ along the colon contracts it lengthwise, causing its walls to bulge and form pouches called _______________.

Circular folds; ceca

Taeniae coli; haustra

Haustra; taeniae coli

Internal sphincters; omental (epiploic) appendages

Internal sphincters; ceca

The muscle tone of the taeniae coli along the colon contracts it lengthwise, causing its walls to bulge and form pouches called haustra.

Explanation

The muscle tone of the taeniae coli along the colon contracts it lengthwise, causing its walls to bulge and form pouches called haustra.

64. _____________ determine/s whether an organism will be genetically male or female.

The sperm

The egg

Both egg and sperm equally

Prenatal hormone exposure

Hormonal, genetic and environmental factors

The sperm determines whether an organism will be genetically male or female because it carries either an X or Y chromosome. If a sperm carrying an X chromosome fertilizes the egg, the resulting organism will be female (XX), while if a sperm carrying a Y chromosome fertilizes the egg, the resulting organism will be male (XY). Therefore, the genetic material present in the sperm determines the sex of the organism.

Explanation

The sperm determines whether an organism will be genetically male or female because it carries either an X or Y chromosome. If a sperm carrying an X chromosome fertilizes the egg, the resulting organism will be female (XX), while if a sperm carrying a Y chromosome fertilizes the egg, the resulting organism will be male (XY). Therefore, the genetic material present in the sperm determines the sex of the organism.

65. The sodium-glucose transport protein (SGLP)

Is a uniport carrier.

Is an antiport carrier.

Uses solvent drag to transport glucose and sodium.

Transports glucose and sodium from the intestinal lumen into the epithelial cells.

Transports glucose from the intestinal lumen into the epithelial cells, and sodium in the opposite direction.

The correct answer is "transports glucose and sodium from the intestinal lumen into the epithelial cells." This is because the sodium-glucose transport protein (SGLP) is responsible for facilitating the movement of both glucose and sodium ions from the intestinal lumen into the epithelial cells. This transport protein plays a crucial role in the absorption of glucose from the intestines into the bloodstream.

Explanation

The correct answer is "transports glucose and sodium from the intestinal lumen into the epithelial cells." This is because the sodium-glucose transport protein (SGLP) is responsible for facilitating the movement of both glucose and sodium ions from the intestinal lumen into the epithelial cells. This transport protein plays a crucial role in the absorption of glucose from the intestines into the bloodstream.

66. Bacterial flora carry out all of the following except

Digest most of the proteins we get in the diet.

Synthesize vitamin K.

Produce some of the gases found in flatus.

Digest cellulose.

Form part of the feces.

Bacterial flora play a crucial role in our digestive system, aiding in the breakdown and absorption of nutrients. They help in the digestion of cellulose, which is a complex carbohydrate found in plant cell walls. They also synthesize vitamin K, which is essential for blood clotting. Additionally, they produce some of the gases found in flatus and form part of the feces. However, the digestion of proteins primarily occurs in the stomach and small intestine through the action of enzymes produced by the human body, rather than by bacterial flora.

Explanation

Bacterial flora play a crucial role in our digestive system, aiding in the breakdown and absorption of nutrients. They help in the digestion of cellulose, which is a complex carbohydrate found in plant cell walls. They also synthesize vitamin K, which is essential for blood clotting. Additionally, they produce some of the gases found in flatus and form part of the feces. However, the digestion of proteins primarily occurs in the stomach and small intestine through the action of enzymes produced by the human body, rather than by bacterial flora.

67. The ______________ gland is an extrinsic salivary gland, whereas the ______________ gland is an intrinsic salivary gland.

Lingual; labial

Submandibular; lingual

Submandibular; sublingual

Sublingual; parotid

Lingual; sublingual

The submandibular gland is an extrinsic salivary gland located underneath the mandible, while the lingual gland is an intrinsic salivary gland located on the underside of the tongue.

Explanation

The submandibular gland is an extrinsic salivary gland located underneath the mandible, while the lingual gland is an intrinsic salivary gland located on the underside of the tongue.

68. Lecithin prepares fats for hydrolysis by forming

Triglycerides, fatty acids, and glycerol.

Low density lipoproteins (LDL).

Chylomicrons.

Emulsification droplets.

Micelles

Lecithin prepares fats for hydrolysis by forming emulsification droplets. Emulsification is the process of breaking down large fat globules into smaller droplets, which increases the surface area available for the action of enzymes that hydrolyze fats. This allows for more efficient digestion and absorption of fats in the body. Emulsification droplets are formed by lecithin, a type of phospholipid, which has both hydrophilic and hydrophobic properties. These droplets help to keep the fat molecules dispersed in water, preventing them from clumping together.

Explanation

Lecithin prepares fats for hydrolysis by forming emulsification droplets. Emulsification is the process of breaking down large fat globules into smaller droplets, which increases the surface area available for the action of enzymes that hydrolyze fats. This allows for more efficient digestion and absorption of fats in the body. Emulsification droplets are formed by lecithin, a type of phospholipid, which has both hydrophilic and hydrophobic properties. These droplets help to keep the fat molecules dispersed in water, preventing them from clumping together.

69. In meiosis, each parent cell produces

Two haploid cells.

Four haploid cells.

Two diploid cells.

Four diploid cells.

Haploid cells identical to the parent cell.

In meiosis, each parent cell undergoes two rounds of cell division, resulting in the formation of four haploid cells. These haploid cells have half the number of chromosomes as the parent cell, allowing for genetic diversity and the formation of gametes for sexual reproduction. Therefore, the correct answer is two haploid cells.

Explanation

In meiosis, each parent cell undergoes two rounds of cell division, resulting in the formation of four haploid cells. These haploid cells have half the number of chromosomes as the parent cell, allowing for genetic diversity and the formation of gametes for sexual reproduction. Therefore, the correct answer is two haploid cells.

70. Crude sounds are formed into intelligible speech by all of the following except

The pharynx.

The epiglottis.

The oral cavity.

The tongue.

The lips.

The epiglottis is not involved in the formation of intelligible speech. It is a flap of cartilage located at the base of the tongue that prevents food and liquid from entering the airway during swallowing. The pharynx, oral cavity, tongue, and lips all play important roles in shaping and articulating sounds to produce speech.

Explanation

The epiglottis is not involved in the formation of intelligible speech. It is a flap of cartilage located at the base of the tongue that prevents food and liquid from entering the airway during swallowing. The pharynx, oral cavity, tongue, and lips all play important roles in shaping and articulating sounds to produce speech.

71. The blood-testis barrier

Prevents antibodies in the blood from getting to the germ cells.

Prevents heat loss from the testes.

Prevents blood from getting to the testes.

Maintains testis temperature at 35°C.

Maintains testis temperature at 37°C.

The blood-testis barrier is a physical barrier that separates the blood vessels from the seminiferous tubules in the testes. It is formed by tight junctions between the Sertoli cells in the seminiferous tubules. This barrier plays a crucial role in protecting the developing germ cells from harmful substances, including antibodies, that may be present in the blood. By preventing antibodies from reaching the germ cells, the blood-testis barrier ensures that they are not attacked by the immune system, which could potentially impair sperm production and fertility.

Explanation

The blood-testis barrier is a physical barrier that separates the blood vessels from the seminiferous tubules in the testes. It is formed by tight junctions between the Sertoli cells in the seminiferous tubules. This barrier plays a crucial role in protecting the developing germ cells from harmful substances, including antibodies, that may be present in the blood. By preventing antibodies from reaching the germ cells, the blood-testis barrier ensures that they are not attacked by the immune system, which could potentially impair sperm production and fertility.

72. Which hormone suppresses spermatogenesis without affecting testosterone secretion?

Gonadotropin-releasing hormone (GnRH)

Testosterone itself

Inhibin

Luteinizing hormone (LH)

Follicle-stimulating hormone (FSH)

Inhibin is the correct answer because it is a hormone that specifically suppresses spermatogenesis without affecting testosterone secretion. It is produced by the Sertoli cells in the testes and acts as a negative feedback signal to inhibit the release of follicle-stimulating hormone (FSH) from the pituitary gland. By inhibiting FSH, inhibin reduces the stimulation of sperm production without affecting the production of testosterone, which is necessary for other male reproductive functions.

Explanation

Inhibin is the correct answer because it is a hormone that specifically suppresses spermatogenesis without affecting testosterone secretion. It is produced by the Sertoli cells in the testes and acts as a negative feedback signal to inhibit the release of follicle-stimulating hormone (FSH) from the pituitary gland. By inhibiting FSH, inhibin reduces the stimulation of sperm production without affecting the production of testosterone, which is necessary for other male reproductive functions.

73. As a result of spermatogenesis and spermiogenesis, the final cells produced are called ____________, but they and all the stages leading up to them can be called ____________.

Sperm cells; interstitial cells

Sperm cells; sustentacular cells

Secondary spermatocytes; spermatocytes in general

Secondary spermatocytes; germ cells

Gametes; germ cells

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Explanation

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74. _________ have 46 chromosomes, whereas _____________ have 23.

Spermatids; spermatozoa

Primary spermatocytes; spermatids

Secondary spermatocytes; primary spermatocytes

Spermatogonia; primary spermatocytes

Type A spermatogonia; type B spermatogonia

Primary spermatocytes are diploid cells that undergo meiosis I to form haploid cells called spermatids. Spermatids then undergo further maturation to form spermatozoa, which are the mature male gametes. Therefore, primary spermatocytes have 46 chromosomes, as they are diploid cells, while spermatids have 23 chromosomes, as they are haploid cells.

Explanation

Primary spermatocytes are diploid cells that undergo meiosis I to form haploid cells called spermatids. Spermatids then undergo further maturation to form spermatozoa, which are the mature male gametes. Therefore, primary spermatocytes have 46 chromosomes, as they are diploid cells, while spermatids have 23 chromosomes, as they are haploid cells.

75. The term menstrual cycle specifically refers to

The sequence of events from fertilization to giving birth.

The events that recur every month during pregnancy.

The cyclic events happening from puberty to menopause.

The cyclic changes in the uterus determined by shifting hormonal changes.

The cyclic changes in the ovaries determined by shifting hormonal changes.

The term menstrual cycle refers to the cyclic changes in the uterus determined by shifting hormonal changes. This includes the shedding of the uterine lining (menstruation) and the preparation of the uterus for possible pregnancy. The cycle typically lasts about 28 days and is regulated by hormones such as estrogen and progesterone. The ovaries also undergo cyclic changes during the menstrual cycle, but the term specifically refers to the changes in the uterus.

Explanation

The term menstrual cycle refers to the cyclic changes in the uterus determined by shifting hormonal changes. This includes the shedding of the uterine lining (menstruation) and the preparation of the uterus for possible pregnancy. The cycle typically lasts about 28 days and is regulated by hormones such as estrogen and progesterone. The ovaries also undergo cyclic changes during the menstrual cycle, but the term specifically refers to the changes in the uterus.

76. The ___________ regulates digestive tract motility, secretion, and blood flow, and its neurons are found in the ____________.

Autonomic nervous system; serosa

Central nervous system; muscularis externa and muscularis mucosae

Enteric nervous system; submucosa and muscularis externa

Visceral sensory division; muscularis externa and submucosa

Visceral motor division; mucosa and submucosa

The enteric nervous system regulates digestive tract motility, secretion, and blood flow, and its neurons are found in the submucosa and muscularis externa.

Explanation

The enteric nervous system regulates digestive tract motility, secretion, and blood flow, and its neurons are found in the submucosa and muscularis externa.

77. The overall purpose of the countercurrent exchange system is

To supply salt and urea to the renal medulla.

To supply nutrients and oxygen to the renal cortex.

To supply nutrients and oxygen to the renal medulla.

To remove metabolic wastes from the renal cortex.

To remove metabolic wastes from the renal medulla.

The countercurrent exchange system is a mechanism that allows for the efficient exchange of substances, such as oxygen and nutrients, between blood vessels in close proximity. In the context of the renal system, the countercurrent exchange system plays a crucial role in maintaining the concentration gradient necessary for the reabsorption of water and solutes. By supplying nutrients and oxygen to the renal medulla, the countercurrent exchange system ensures that the medulla has the necessary resources to carry out its functions, such as concentrating urine and regulating water balance.

Explanation

The countercurrent exchange system is a mechanism that allows for the efficient exchange of substances, such as oxygen and nutrients, between blood vessels in close proximity. In the context of the renal system, the countercurrent exchange system plays a crucial role in maintaining the concentration gradient necessary for the reabsorption of water and solutes. By supplying nutrients and oxygen to the renal medulla, the countercurrent exchange system ensures that the medulla has the necessary resources to carry out its functions, such as concentrating urine and regulating water balance.

78. Which of these induces renin secretion, constricts afferent arterioles, and reduces GFR, and urine volume?

Aldosterone

Antidiuretic hormone

Parathyroid hormone

Norepinephrine

Angiotensin II

Norepinephrine induces renin secretion, constricts afferent arterioles, and reduces GFR (glomerular filtration rate) and urine volume. Norepinephrine is a neurotransmitter and hormone that is released by the sympathetic nervous system in response to stress or low blood pressure. It acts on the kidneys to decrease blood flow and filtration, which helps to conserve water and increase blood volume. This response is part of the body's physiological mechanism to maintain blood pressure and fluid balance.

Explanation

Norepinephrine induces renin secretion, constricts afferent arterioles, and reduces GFR (glomerular filtration rate) and urine volume. Norepinephrine is a neurotransmitter and hormone that is released by the sympathetic nervous system in response to stress or low blood pressure. It acts on the kidneys to decrease blood flow and filtration, which helps to conserve water and increase blood volume. This response is part of the body's physiological mechanism to maintain blood pressure and fluid balance.

79.

In ___, the lungs are infected with Mycobacterium and produce fibrous nodules around the bacteria, leading to progressive pulmonary fibrosis.

Pneumonia

Dyspnea

Pneumothorax

Tuberculosis

Rhinitis

In tuberculosis, the lungs are infected with Mycobacterium and produce fibrous nodules around the bacteria, leading to progressive pulmonary fibrosis. This infection causes inflammation and damage to the lung tissue, resulting in the formation of scar tissue. Over time, the scar tissue can build up and restrict the normal functioning of the lungs, leading to symptoms such as coughing, chest pain, and difficulty breathing.

Explanation

In tuberculosis, the lungs are infected with Mycobacterium and produce fibrous nodules around the bacteria, leading to progressive pulmonary fibrosis. This infection causes inflammation and damage to the lung tissue, resulting in the formation of scar tissue. Over time, the scar tissue can build up and restrict the normal functioning of the lungs, leading to symptoms such as coughing, chest pain, and difficulty breathing.

80. The orgasm-emission phase of the male sexual response is stimulated by

Efferent sympathetic signals from the sacral region of the spinal cord.

Efferent sympathetic signals from the lumbar region of the spinal cord.

Efferent parasympathetic signals from the sacral region of the spinal cord.

Efferent parasympathetic signals from the lumbar region of the spinal cord.

Efferent somatic signals from the thoracic region of the spinal cord

The correct answer is efferent sympathetic signals from the lumbar region of the spinal cord. During the orgasm-emission phase of the male sexual response, the sympathetic nervous system is activated. This leads to the release of sympathetic signals from the lumbar region of the spinal cord, which stimulate the contraction of various muscles involved in ejaculation and the expulsion of semen.

Explanation

The correct answer is efferent sympathetic signals from the lumbar region of the spinal cord. During the orgasm-emission phase of the male sexual response, the sympathetic nervous system is activated. This leads to the release of sympathetic signals from the lumbar region of the spinal cord, which stimulate the contraction of various muscles involved in ejaculation and the expulsion of semen.

81. The vagus and glossopharyngeal nerves carry afferent signals from peripheral chemoreceptors to a chemosensitive area in

The pontine respiratory group.

The dorsal respiratory group.

The ventral respiratory group.

The medulla oblongata.

The pons.

The vagus and glossopharyngeal nerves are responsible for carrying afferent signals from peripheral chemoreceptors to a chemosensitive area. The medulla oblongata is a part of the brainstem located in the lower part of the brain, which plays a crucial role in controlling respiratory functions. It contains the chemosensitive area where these afferent signals are received and processed. Therefore, the medulla oblongata is the correct answer as it is the specific location where these signals are transmitted to.

Explanation

The vagus and glossopharyngeal nerves are responsible for carrying afferent signals from peripheral chemoreceptors to a chemosensitive area. The medulla oblongata is a part of the brainstem located in the lower part of the brain, which plays a crucial role in controlling respiratory functions. It contains the chemosensitive area where these afferent signals are received and processed. Therefore, the medulla oblongata is the correct answer as it is the specific location where these signals are transmitted to.

82.

The blood transports more CO₂ in the form of ___ than in any other form.

Carbaminohemoglobin

Carboxyhemoglobin

Bicarbonate ions

Dissolved CO2 gas

Bisphosphocarbonate

The blood transports more CO2 in the form of bicarbonate ions than in any other form. When CO2 enters the bloodstream, it combines with water to form carbonic acid, which then dissociates into bicarbonate ions and hydrogen ions. The majority of CO2 in the blood is carried as bicarbonate ions, which are highly soluble and can easily be transported throughout the body. This helps to maintain the pH balance in the blood and allows for efficient removal of CO2 from the tissues.

Explanation

The blood transports more CO2 in the form of bicarbonate ions than in any other form. When CO2 enters the bloodstream, it combines with water to form carbonic acid, which then dissociates into bicarbonate ions and hydrogen ions. The majority of CO2 in the blood is carried as bicarbonate ions, which are highly soluble and can easily be transported throughout the body. This helps to maintain the pH balance in the blood and allows for efficient removal of CO2 from the tissues.

83.

Deep, rapid breathing often seen in terminal diabetes mellitus is known as what?

Tachypnea

Dyspnea

Orthopnea

Hyperpnea

Kussmaul respiration

Kussmaul respiration refers to deep, rapid breathing that is often observed in individuals with terminal diabetes mellitus. This type of breathing pattern is characterized by increased depth and rate of breathing, and it is a compensatory mechanism used by the body to get rid of excess acid (ketones) in the blood. This is commonly seen in diabetic ketoacidosis, a life-threatening condition that occurs when there is a buildup of ketones in the blood. Kussmaul respiration helps to blow off the excess carbon dioxide and acid from the body, aiming to restore the acid-base balance.

Explanation

Kussmaul respiration refers to deep, rapid breathing that is often observed in individuals with terminal diabetes mellitus. This type of breathing pattern is characterized by increased depth and rate of breathing, and it is a compensatory mechanism used by the body to get rid of excess acid (ketones) in the blood. This is commonly seen in diabetic ketoacidosis, a life-threatening condition that occurs when there is a buildup of ketones in the blood. Kussmaul respiration helps to blow off the excess carbon dioxide and acid from the body, aiming to restore the acid-base balance.

84. The most important role of meiosis in sexual reproduction is

That it reduces the size of the gametes.

That it produces at least one gamete that is mobile.

That it prevents the chromosome number from doubling in each generation.

That it ensures that each daughter cell doubles the number of chromosomes.

That it changes the genetic composition of each chromosome.

Meiosis is a type of cell division that is specifically involved in the production of gametes (sperm and eggs) in sexual reproduction. The main purpose of meiosis is to halve the number of chromosomes in the resulting gametes, ensuring that the offspring will have the correct number of chromosomes. If meiosis did not occur, the chromosome number would double with each generation, leading to an unmanageable number of chromosomes and genetic material. Therefore, the most important role of meiosis in sexual reproduction is to prevent the chromosome number from doubling in each generation.

Explanation

Meiosis is a type of cell division that is specifically involved in the production of gametes (sperm and eggs) in sexual reproduction. The main purpose of meiosis is to halve the number of chromosomes in the resulting gametes, ensuring that the offspring will have the correct number of chromosomes. If meiosis did not occur, the chromosome number would double with each generation, leading to an unmanageable number of chromosomes and genetic material. Therefore, the most important role of meiosis in sexual reproduction is to prevent the chromosome number from doubling in each generation.

85.

Which malignancy originates in the lamina propria of the bronchi?

Squamous-cell carcinoma

Oat-cell carcinoma

Adenocarcinoma

Pulmonary edema

Cor pulmonale

Adenocarcinoma is a type of malignancy that originates in the glandular cells of the bronchi. The lamina propria is a layer of connective tissue that supports the bronchial epithelium, and adenocarcinoma can develop within this layer. Squamous-cell carcinoma and oat-cell carcinoma are other types of lung cancer, but they do not specifically originate in the lamina propria. Pulmonary edema and cor pulmonale are not malignancies, but rather conditions related to fluid accumulation in the lungs and right-sided heart failure, respectively.

Explanation

Adenocarcinoma is a type of malignancy that originates in the glandular cells of the bronchi. The lamina propria is a layer of connective tissue that supports the bronchial epithelium, and adenocarcinoma can develop within this layer. Squamous-cell carcinoma and oat-cell carcinoma are other types of lung cancer, but they do not specifically originate in the lamina propria. Pulmonary edema and cor pulmonale are not malignancies, but rather conditions related to fluid accumulation in the lungs and right-sided heart failure, respectively.

86. The basis of pregnancy test kits is the presence of ____________, which is secreted by the _________________.

Human chorionic somatomammotropin; endometrium and myometrium

Human chorionic gonadotropin (HCG); blastocyst and placenta

Progesterone; corpus luteum and corpus albicans

Progesterone; blastocyst and embryo

Estrogens; blastocyst and placenta

The basis of pregnancy test kits is the presence of human chorionic gonadotropin (HCG), which is secreted by the blastocyst and placenta. This hormone is produced after fertilization occurs and is responsible for maintaining the pregnancy. The presence of HCG in a woman's urine or blood indicates that she is pregnant, which is detected by the test kit.

Explanation

The basis of pregnancy test kits is the presence of human chorionic gonadotropin (HCG), which is secreted by the blastocyst and placenta. This hormone is produced after fertilization occurs and is responsible for maintaining the pregnancy. The presence of HCG in a woman's urine or blood indicates that she is pregnant, which is detected by the test kit.

87. Which of the following does not have cilia?

The nasal cavity

The trachea

The bronchi

Terminal bronchioles

Respiratory bronchioles

The respiratory bronchioles do not have cilia. Cilia are small hair-like structures that help in moving mucus and trapped particles out of the respiratory system. They are present in the nasal cavity, trachea, bronchi, and terminal bronchioles, but not in the respiratory bronchioles. This is because the respiratory bronchioles are the smallest airways in the lungs and are primarily involved in gas exchange rather than mucus clearance.

Explanation

The respiratory bronchioles do not have cilia. Cilia are small hair-like structures that help in moving mucus and trapped particles out of the respiratory system. They are present in the nasal cavity, trachea, bronchi, and terminal bronchioles, but not in the respiratory bronchioles. This is because the respiratory bronchioles are the smallest airways in the lungs and are primarily involved in gas exchange rather than mucus clearance.

88. Tom is in respiratory arrest due to an electrical shock. Why does a Good Samaritan have up to 4 or 5 minutes to begin CPR and save Tom's life?

Reserve oxygen in Tom's lungs

A venous reserve of oxygen in Tom's blood

The ambient Po2 can support life that long

The Haldane effect lasts up to 5 minutes

Tom's hypoxic drive will keep him alive for up to 5 minutes

A Good Samaritan has up to 4 or 5 minutes to begin CPR and save Tom's life because there is a venous reserve of oxygen in Tom's blood. This means that even if Tom's breathing has stopped due to respiratory arrest, there is still a small amount of oxygen left in his blood that can support his vital organs for a short period of time. Starting CPR within this timeframe can help maintain blood circulation and oxygenate the organs until professional medical help arrives.

Explanation

A Good Samaritan has up to 4 or 5 minutes to begin CPR and save Tom's life because there is a venous reserve of oxygen in Tom's blood. This means that even if Tom's breathing has stopped due to respiratory arrest, there is still a small amount of oxygen left in his blood that can support his vital organs for a short period of time. Starting CPR within this timeframe can help maintain blood circulation and oxygenate the organs until professional medical help arrives.

89. The addition of CO₂ to the blood generates ___ ions in the RBCs, which in turn stimulates RBCs to unload more oxygen.

Sodium

Potassium

Nitrogen

Hydrogen

Chloride

When CO2 is added to the blood, it reacts with water to form carbonic acid (H2CO3). This dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-). The increase in hydrogen ions in the red blood cells (RBCs) triggers a series of reactions that result in the release of more oxygen from hemoglobin. This is known as the Bohr effect, where increased acidity (higher hydrogen ion concentration) causes oxygen to be released more readily from hemoglobin. Therefore, the addition of CO2 generates hydrogen ions in the RBCs, stimulating them to unload more oxygen.

Explanation

When CO2 is added to the blood, it reacts with water to form carbonic acid (H2CO3). This dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-). The increase in hydrogen ions in the red blood cells (RBCs) triggers a series of reactions that result in the release of more oxygen from hemoglobin. This is known as the Bohr effect, where increased acidity (higher hydrogen ion concentration) causes oxygen to be released more readily from hemoglobin. Therefore, the addition of CO2 generates hydrogen ions in the RBCs, stimulating them to unload more oxygen.

90. From their formation to ejaculation, sperm cells take the following pathway:

Seminiferous tubule, epididymis, rete testis, urethra, ejaculatory duct, ductus deferens.

Seminiferous tubule, epididymis, rete testis, ejaculatory duct, ductus deferens, urethra.

Seminiferous tubule, epididymis, rete testis, ductus deferens, ejaculatory duct, urethra.

Seminiferous tubule, rete testis, epididymis, ductus deferens, ejaculatory duct, urethra.

Seminiferous tubule, rete testis, epididymis, ejaculatory duct, urethra, ductus deferens.

Sperm cells are produced in the seminiferous tubules of the testes. From there, they travel to the rete testis, which is a network of tubules that connects the seminiferous tubules to the epididymis. The sperm cells then move into the epididymis, where they mature and are stored. When ejaculation occurs, the sperm cells are transported through the ductus deferens, which is a long muscular tube that connects the epididymis to the ejaculatory duct. The ejaculatory duct then joins with the urethra, which is the final pathway for the sperm cells to leave the body. Therefore, the correct pathway is seminiferous tubule, rete testis, epididymis, ductus deferens, ejaculatory duct, urethra.

Explanation

Sperm cells are produced in the seminiferous tubules of the testes. From there, they travel to the rete testis, which is a network of tubules that connects the seminiferous tubules to the epididymis. The sperm cells then move into the epididymis, where they mature and are stored. When ejaculation occurs, the sperm cells are transported through the ductus deferens, which is a long muscular tube that connects the epididymis to the ejaculatory duct. The ejaculatory duct then joins with the urethra, which is the final pathway for the sperm cells to leave the body. Therefore, the correct pathway is seminiferous tubule, rete testis, epididymis, ductus deferens, ejaculatory duct, urethra.

91. What is the basic distinction between an alveolar duct and an alveolar atrium?

Their shape

Their size

Their function

Their epithelial type

Presence or absence of cilia

The basic distinction between an alveolar duct and an alveolar atrium is their shape.

Explanation

The basic distinction between an alveolar duct and an alveolar atrium is their shape.

92. After puberty, the vaginal lining becomes _________ to ________.

Simple squamous epithelium; allow fast diffusion of nutrients in case a zygote is implanted

Transitional epithelium; provide more elasticity necessary for coitus and delivery

Simple columnar; facilitate sperm absorption and secretion of vaginal lubricants

Simple cuboidal; provide protection and lubrication

Stratified squamous epithelium; resist abrasion

After puberty, the vaginal lining becomes stratified squamous epithelium to resist abrasion. This type of epithelium is composed of multiple layers of flattened cells, which provide a protective barrier against friction and potential damage during sexual intercourse and childbirth. The stratified squamous epithelium is well-suited for its role in the vagina, as it can withstand mechanical stress and abrasion while maintaining the integrity of the tissue.

Explanation

After puberty, the vaginal lining becomes stratified squamous epithelium to resist abrasion. This type of epithelium is composed of multiple layers of flattened cells, which provide a protective barrier against friction and potential damage during sexual intercourse and childbirth. The stratified squamous epithelium is well-suited for its role in the vagina, as it can withstand mechanical stress and abrasion while maintaining the integrity of the tissue.

93. Polio can sometimes damage the brainstem respiratory centers and result in

A Bohr effect.

Adult respiratory distress syndrome.

Pneumothorax.

Atelectasis.

Ondine's curse.

Ondine's curse, also known as congenital central hypoventilation syndrome (CCHS), is a rare condition in which the automatic control of breathing is impaired. This means that affected individuals may not breathe adequately while asleep, leading to respiratory difficulties. In some cases, polio can cause damage to the brainstem respiratory centers, resulting in Ondine's curse. The other options listed, such as the Bohr effect, adult respiratory distress syndrome, pneumothorax, and atelectasis, are not directly related to polio or the impairment of respiratory centers in the brainstem.

Explanation

Ondine's curse, also known as congenital central hypoventilation syndrome (CCHS), is a rare condition in which the automatic control of breathing is impaired. This means that affected individuals may not breathe adequately while asleep, leading to respiratory difficulties. In some cases, polio can cause damage to the brainstem respiratory centers, resulting in Ondine's curse. The other options listed, such as the Bohr effect, adult respiratory distress syndrome, pneumothorax, and atelectasis, are not directly related to polio or the impairment of respiratory centers in the brainstem.

94. Nitrogen bubbles can form in the blood and other tissues when a scuba diver ascends too rapidly, producing a syndrome called

Decompression sickness.

Hyperbaric disease.

Cerebral embolism.

Pulmonary barotrauma.

Pulmonary edema.The vagus and glossopharyngeal nerves carry afferent signals from peripheral chemoreceptors to a chemosensitive area inpulmonary edema.pulmonary edema.

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Explanation

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95.

The upper respiratory tract extends

From the nose through the trachea.

From the nose through the pharynx.

From the nose through the larynx.

From the nose through the alveoli.

From the nose through the lungs.

The upper respiratory tract refers to the portion of the respiratory system that is located above the lungs. It includes the nose, nasal passages, pharynx, and larynx. The correct answer states that the upper respiratory tract extends from the nose through the larynx, which is accurate. The trachea, alveoli, and lungs are not part of the upper respiratory tract.

Explanation

The upper respiratory tract refers to the portion of the respiratory system that is located above the lungs. It includes the nose, nasal passages, pharynx, and larynx. The correct answer states that the upper respiratory tract extends from the nose through the larynx, which is accurate. The trachea, alveoli, and lungs are not part of the upper respiratory tract.

96.

The amount of air in excess of tidal volume that can be inhaled with maximum effort is called

Vital capacity.

Inspiratory reserve volume.

Expiratory reserve volume.

Residual volume.

Inspiratory capacity.

The inspiratory reserve volume refers to the amount of air that can be inhaled with maximum effort after a normal tidal volume inhalation. It represents the additional air that can be taken in beyond the normal breathing capacity.

Explanation

The inspiratory reserve volume refers to the amount of air that can be inhaled with maximum effort after a normal tidal volume inhalation. It represents the additional air that can be taken in beyond the normal breathing capacity.

97.

Carbon dioxide is transported by all the following means except

Carbaminohemoglobin.

Carbonic acid.

Bicarbonate ions.

Carbonate

Dissolved gas.

Carbon dioxide is transported in the blood through three main forms: carbaminohemoglobin, carbonic acid, and bicarbonate ions. Carbonate is not involved in the transportation of carbon dioxide in the blood. Therefore, carbonate is the correct answer as it is not one of the means by which carbon dioxide is transported.

Explanation

Carbon dioxide is transported in the blood through three main forms: carbaminohemoglobin, carbonic acid, and bicarbonate ions. Carbonate is not involved in the transportation of carbon dioxide in the blood. Therefore, carbonate is the correct answer as it is not one of the means by which carbon dioxide is transported.

98. The ovulated egg is at

Prophase I.

Metaphase I.

Telophase I.

Prophase II.

Metaphase II

Metaphase II is the correct answer because it is the stage in meiosis where the chromosomes align at the equatorial plate of the cell. This occurs after the first round of cell division (meiosis I) where homologous chromosomes separate. In metaphase II, the sister chromatids of each chromosome line up individually, ready to be separated in the subsequent anaphase II. Therefore, metaphase II is the stage where the ovulated egg is at in meiosis.

Explanation

Metaphase II is the correct answer because it is the stage in meiosis where the chromosomes align at the equatorial plate of the cell. This occurs after the first round of cell division (meiosis I) where homologous chromosomes separate. In metaphase II, the sister chromatids of each chromosome line up individually, ready to be separated in the subsequent anaphase II. Therefore, metaphase II is the stage where the ovulated egg is at in meiosis.

99. Which of these does not leave a follicle when it ovulates?

A secondary oocyte

A zona pellucida

A corona radiata

A second polar body

The theca folliculi

During ovulation, a secondary oocyte is released from the ovary. This oocyte is surrounded by a protective layer called the zona pellucida, which helps in fertilization. The corona radiata is another layer of cells that surrounds the oocyte. Both the zona pellucida and the corona radiata are shed during fertilization. However, a second polar body is a small non-functional cell that is formed during meiosis. It does not have a follicle and is not involved in fertilization. Therefore, the second polar body does not leave a follicle when it ovulates.

Explanation

During ovulation, a secondary oocyte is released from the ovary. This oocyte is surrounded by a protective layer called the zona pellucida, which helps in fertilization. The corona radiata is another layer of cells that surrounds the oocyte. Both the zona pellucida and the corona radiata are shed during fertilization. However, a second polar body is a small non-functional cell that is formed during meiosis. It does not have a follicle and is not involved in fertilization. Therefore, the second polar body does not leave a follicle when it ovulates.

100. ____________ inhibit/s the secretion of ____________ during the female sexual cycle.

GnRH; FSH and LH

Estradiol and progesterone; FSH and LH

Estradiol; progesterone

Estradiol; LH

FSH and LH; androgens

Estradiol and progesterone inhibit the secretion of FSH and LH during the female sexual cycle. These hormones are produced by the ovaries and play a crucial role in regulating the menstrual cycle. Estradiol and progesterone work together to suppress the release of FSH and LH from the pituitary gland, which in turn helps to regulate the development and release of eggs from the ovaries. This feedback mechanism helps to maintain hormonal balance and ensure proper functioning of the reproductive system.

Explanation

Estradiol and progesterone inhibit the secretion of FSH and LH during the female sexual cycle. These hormones are produced by the ovaries and play a crucial role in regulating the menstrual cycle. Estradiol and progesterone work together to suppress the release of FSH and LH from the pituitary gland, which in turn helps to regulate the development and release of eggs from the ovaries. This feedback mechanism helps to maintain hormonal balance and ensure proper functioning of the reproductive system.

101. The basis for contraceptive pills is that they mimic the ____________ feedback effect of ____________.

Positive; FSH and LH

Positive; estrogens and progesterone

Negative; FSH and LH

Negative; human chorionic gonadotropin (HCG)

Negative; estrogens and progesterone

Contraceptive pills mimic the negative feedback effect of estrogens and progesterone. Estrogens and progesterone are hormones that are naturally produced by the body during the menstrual cycle. When the levels of these hormones rise, they signal the brain to decrease the production of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which are responsible for stimulating the release of eggs from the ovaries. By mimicking this negative feedback effect, contraceptive pills help to prevent ovulation and therefore prevent pregnancy.

Explanation

Contraceptive pills mimic the negative feedback effect of estrogens and progesterone. Estrogens and progesterone are hormones that are naturally produced by the body during the menstrual cycle. When the levels of these hormones rise, they signal the brain to decrease the production of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which are responsible for stimulating the release of eggs from the ovaries. By mimicking this negative feedback effect, contraceptive pills help to prevent ovulation and therefore prevent pregnancy.

102. Glucose and amino acids are reabsorbed from the glomerular filtrate by

The renal corpuscle.

The proximal convoluted tubule.

The distal convoluted tubule.

The collecting duct.

The glomerular capillaries.

Glucose and amino acids are reabsorbed from the glomerular filtrate by the proximal convoluted tubule. This is because the proximal convoluted tubule is the first segment of the renal tubule and it plays a major role in reabsorbing valuable substances from the filtrate back into the bloodstream. It has a large surface area and is lined with specialized cells that actively transport glucose and amino acids from the tubule lumen into the surrounding capillaries. This reabsorption process helps to maintain the body's glucose and amino acid levels and prevent their loss in the urine.

Explanation

Glucose and amino acids are reabsorbed from the glomerular filtrate by the proximal convoluted tubule. This is because the proximal convoluted tubule is the first segment of the renal tubule and it plays a major role in reabsorbing valuable substances from the filtrate back into the bloodstream. It has a large surface area and is lined with specialized cells that actively transport glucose and amino acids from the tubule lumen into the surrounding capillaries. This reabsorption process helps to maintain the body's glucose and amino acid levels and prevent their loss in the urine.

103.

Congestive heart failure results in which of the following?

Hypoxemic hypoxia

Ischemic hypoxia

Anemic hypoxia

Histotoxic hypoxia

Idiopathic hypoxia

Congestive heart failure can lead to ischemic hypoxia. Ischemic hypoxia occurs when there is a decrease in blood flow and oxygen supply to the tissues. In congestive heart failure, the heart is unable to pump blood effectively, leading to reduced blood flow to various organs and tissues. This can result in inadequate oxygen delivery to the tissues, causing ischemic hypoxia.

Explanation

Congestive heart failure can lead to ischemic hypoxia. Ischemic hypoxia occurs when there is a decrease in blood flow and oxygen supply to the tissues. In congestive heart failure, the heart is unable to pump blood effectively, leading to reduced blood flow to various organs and tissues. This can result in inadequate oxygen delivery to the tissues, causing ischemic hypoxia.

104. Erection is

An autonomic reflex mediated predominantly by parasympathetic nerve fibers.

An autonomic reflex mediated predominantly by sympathetic nerve fibers.

A somatic reflex mediated predominantly by parasympathetic nerve fibers.

A somatic reflex mediated predominantly by sympathetic nerve fibers.

An exclusively voluntary action mediated by the cerebral cortex.

Erection is an autonomic reflex mediated predominantly by parasympathetic nerve fibers. This means that the parasympathetic nervous system, which is responsible for rest and relaxation, plays a major role in causing an erection. The parasympathetic nerves release neurotransmitters that promote the relaxation of smooth muscle in the arteries of the penis, allowing for increased blood flow and ultimately leading to an erection. While sympathetic nerve fibers also contribute to the process, the parasympathetic system is the primary mediator of this reflex.

Explanation

Erection is an autonomic reflex mediated predominantly by parasympathetic nerve fibers. This means that the parasympathetic nervous system, which is responsible for rest and relaxation, plays a major role in causing an erection. The parasympathetic nerves release neurotransmitters that promote the relaxation of smooth muscle in the arteries of the penis, allowing for increased blood flow and ultimately leading to an erection. While sympathetic nerve fibers also contribute to the process, the parasympathetic system is the primary mediator of this reflex.

105. After expelling the oocyte, the follicle becomes the ____________ and secretes __________.

Corpus albicans; FSH and LH

Corpus albicans; estrogen and progesterone

Corpus luteum; FSH and LH

Corpus luteum; estrogen and progesterone

Corpus albicans; progesterone

After expelling the oocyte, the follicle becomes the corpus luteum and secretes estrogen and progesterone.

Explanation

After expelling the oocyte, the follicle becomes the corpus luteum and secretes estrogen and progesterone.

106.

Blood banks dispose of blood that has low levels of bisphosphoglycerate. What would be the probable reason for doing so?

A low BPG level causes acidosis of blood.

Erythrocytes low in BPG do not unload CO2 very well.

Erythrocytes low in BPG do not unload O2 very well.

Erythrocytes low in BPG do not load O2 very well.

A decline in BPG level is accompanied by a decline in hemoglobin level.

Erythrocytes (red blood cells) contain an enzyme called bisphosphoglycerate mutase, which helps in the release of oxygen from hemoglobin. Bisphosphoglycerate (BPG) binds to hemoglobin and reduces its affinity for oxygen, allowing it to be released to the tissues. When the level of BPG is low, erythrocytes are unable to unload oxygen efficiently, leading to decreased oxygen supply to the tissues. Therefore, blood banks dispose of blood with low levels of BPG to ensure that the blood being transfused can effectively deliver oxygen to the body.

Explanation

Erythrocytes (red blood cells) contain an enzyme called bisphosphoglycerate mutase, which helps in the release of oxygen from hemoglobin. Bisphosphoglycerate (BPG) binds to hemoglobin and reduces its affinity for oxygen, allowing it to be released to the tissues. When the level of BPG is low, erythrocytes are unable to unload oxygen efficiently, leading to decreased oxygen supply to the tissues. Therefore, blood banks dispose of blood with low levels of BPG to ensure that the blood being transfused can effectively deliver oxygen to the body.

107. During the proliferative phase of the menstrual cycle

Several follicles are developing antrums.

The corpus luteum is enlarging.

Oogonia are transforming into primary oocytes.

The oocyte completes meiosis II.

The corpus luteum is shrinking.

During the proliferative phase of the menstrual cycle, several follicles are developing antrums. This is because the proliferative phase is characterized by the growth and development of multiple ovarian follicles. Antrums are fluid-filled spaces that form within the follicles, and their development is necessary for the maturation of the oocyte. The follicles produce estrogen, which stimulates the growth of the endometrium in preparation for potential implantation of a fertilized egg. As the follicles develop antrums, one dominant follicle will eventually ovulate, releasing a mature oocyte for potential fertilization.

Explanation

During the proliferative phase of the menstrual cycle, several follicles are developing antrums. This is because the proliferative phase is characterized by the growth and development of multiple ovarian follicles. Antrums are fluid-filled spaces that form within the follicles, and their development is necessary for the maturation of the oocyte. The follicles produce estrogen, which stimulates the growth of the endometrium in preparation for potential implantation of a fertilized egg. As the follicles develop antrums, one dominant follicle will eventually ovulate, releasing a mature oocyte for potential fertilization.

108. During exercise, which of the following directly increases respiratory rate?

Increased H+ level in the blood

The Bohr effect

Reduced blood pH

Reduced oxyhemoglobin

Anticipation of the needs of exercising muscle

During exercise, the respiratory rate increases in order to meet the increased oxygen demand of the muscles. Anticipation of the needs of the exercising muscle triggers the respiratory centers in the brain to increase the rate and depth of breathing, allowing for more oxygen to be taken in and carbon dioxide to be expelled. This response is a result of the body's attempt to maintain homeostasis and ensure an adequate supply of oxygen to the working muscles.

Explanation

During exercise, the respiratory rate increases in order to meet the increased oxygen demand of the muscles. Anticipation of the needs of the exercising muscle triggers the respiratory centers in the brain to increase the rate and depth of breathing, allowing for more oxygen to be taken in and carbon dioxide to be expelled. This response is a result of the body's attempt to maintain homeostasis and ensure an adequate supply of oxygen to the working muscles.

109. In the adult ovary, more than 90% of the follicles are found as

Primary follicles.

Secondary follicles.

Tertiary follicle.

Mature (graafian) follicles.

Primordial follicles.

In the adult ovary, the majority of follicles are in the primordial stage. Primordial follicles are the earliest stage of follicle development and are characterized by a single layer of flattened cells surrounding an immature egg. These follicles are in a dormant state and can remain in this stage for several years before they are activated to develop further. Therefore, it is the primordial follicles that make up more than 90% of the follicles in the adult ovary.

Explanation

In the adult ovary, the majority of follicles are in the primordial stage. Primordial follicles are the earliest stage of follicle development and are characterized by a single layer of flattened cells surrounding an immature egg. These follicles are in a dormant state and can remain in this stage for several years before they are activated to develop further. Therefore, it is the primordial follicles that make up more than 90% of the follicles in the adult ovary.

110. During the follicular phase, granulosa cells secrete ____________, which stimulates secretion of ___________.

Estradiol; LH

Estradiol; FSH

Estradiol; GnRH

Progesterone; FSH

Progesterone; LH

During the follicular phase of the menstrual cycle, granulosa cells in the ovaries secrete estradiol. Estradiol then stimulates the secretion of luteinizing hormone (LH) from the pituitary gland. LH plays a crucial role in triggering ovulation and the release of the mature egg from the ovary. Therefore, the correct answer is estradiol; LH.

Explanation

During the follicular phase of the menstrual cycle, granulosa cells in the ovaries secrete estradiol. Estradiol then stimulates the secretion of luteinizing hormone (LH) from the pituitary gland. LH plays a crucial role in triggering ovulation and the release of the mature egg from the ovary. Therefore, the correct answer is estradiol; LH.

111. Which of these blood hormone levels reaches its maximum during the luteal phase?

GnRH

FSH

LH

Progesterone

Estradiol

During the luteal phase, the corpus luteum, which is formed from the ruptured follicle after ovulation, secretes progesterone. Progesterone is responsible for preparing the uterus for implantation of a fertilized egg and maintaining pregnancy. Therefore, progesterone levels reach their maximum during the luteal phase. GnRH, FSH, LH, and estradiol are also involved in the menstrual cycle but do not reach their maximum levels during the luteal phase.

Explanation

During the luteal phase, the corpus luteum, which is formed from the ruptured follicle after ovulation, secretes progesterone. Progesterone is responsible for preparing the uterus for implantation of a fertilized egg and maintaining pregnancy. Therefore, progesterone levels reach their maximum during the luteal phase. GnRH, FSH, LH, and estradiol are also involved in the menstrual cycle but do not reach their maximum levels during the luteal phase.

112. Which of the following is not a function of the respiratory system?

It helps control the pH of body fluids.

It promotes the flow of lymph and venous blood.

It assists in the synthesis of vasodilators.

It helps with defecation.

The respiratory system helps control the pH of body fluids by regulating the levels of carbon dioxide and oxygen in the blood through breathing. It promotes the flow of lymph and venous blood by the action of breathing which helps circulate these fluids. However, it does not assist in the synthesis of vasodilators. Vasodilators are substances that widen blood vessels, and this function is not directly related to the respiratory system.

Explanation

The respiratory system helps control the pH of body fluids by regulating the levels of carbon dioxide and oxygen in the blood through breathing. It promotes the flow of lymph and venous blood by the action of breathing which helps circulate these fluids. However, it does not assist in the synthesis of vasodilators. Vasodilators are substances that widen blood vessels, and this function is not directly related to the respiratory system.

113. Which of the following has no effect on oxyhemoglobin dissociation?

Epinephrine

Fever

Thyroid hormone

Low pH

Erythrocyte count

Erythrocyte count refers to the number of red blood cells in the body. Oxyhemoglobin dissociation is the process by which oxygen is released from hemoglobin in the blood to be used by tissues. Erythrocyte count does not directly affect this process. Instead, factors such as epinephrine, fever, thyroid hormone, and low pH can influence the affinity of hemoglobin for oxygen and therefore impact oxyhemoglobin dissociation.

Explanation

Erythrocyte count refers to the number of red blood cells in the body. Oxyhemoglobin dissociation is the process by which oxygen is released from hemoglobin in the blood to be used by tissues. Erythrocyte count does not directly affect this process. Instead, factors such as epinephrine, fever, thyroid hormone, and low pH can influence the affinity of hemoglobin for oxygen and therefore impact oxyhemoglobin dissociation.