1.
The respiratory tract
Correct Answer
B. Contains conductance, resistance, and exchange structures
Explanation
The correct answer is "contains conductance, resistance, and exchange structures." The respiratory tract is responsible for the exchange of oxygen and carbon dioxide between the body and the environment. It includes various structures such as the nose, mouth, pharynx, larynx, trachea, bronchi, and bronchioles. These structures are involved in conducting air into and out of the lungs, providing resistance to airflow, and facilitating the exchange of gases in the alveoli.
2.
Contraction and relaxation of the diaphragm and intercostal muscles
Correct Answer
A. Is responsible for ventilation
Explanation
The contraction and relaxation of the diaphragm and intercostal muscles is responsible for ventilation. This refers to the process of breathing, where the diaphragm contracts and moves downward while the intercostal muscles contract, causing the ribcage to expand. This creates a pressure difference, allowing air to enter the lungs during inhalation. During exhalation, the diaphragm and intercostal muscles relax, causing the ribcage to move back to its original position and expel air from the lungs. Therefore, the contraction and relaxation of these muscles play a crucial role in the ventilation process.
3.
Contraction and relaxation of the diaphragm and intercostal muscles
Correct Answer
D. Changes thoracic volume
Explanation
The contraction and relaxation of the diaphragm and intercostal muscles directly affect the thoracic volume. When these muscles contract, the volume of the thoracic cavity increases, creating a negative pressure within the lungs. This negative pressure allows air to rush into the lungs, facilitating inhalation. On the other hand, when these muscles relax, the thoracic volume decreases, causing an increase in pressure within the lungs, leading to exhalation. Therefore, the changes in thoracic volume play a crucial role in ventilation by facilitating the movement of air in and out of the lungs.
4.
Which of the following is least related to the alveoli?
Correct Answer
C. Contains smooth muscle that determines the flow of air through the respiratory passages
Explanation
The alveoli are tiny air sacs in the lungs where the exchange of respiratory gases takes place. They are not directly related to the smooth muscle that determines the flow of air through the respiratory passages, as this function is primarily carried out by the bronchial tree. The presence of surfactant in the alveoli helps to reduce surface tension and prevent their collapse. Therefore, the option "contains smooth muscle that determines the flow of air through the respiratory passages" is least related to the alveoli.
5.
Which of the following prevents the collapse of the trachea?
Correct Answer
D. Cartilaginous rings
Explanation
The cartilaginous rings prevent the collapse of the trachea. These rings provide structural support to the tracheal walls, ensuring that they remain open and do not collapse during inhalation and exhalation. The rings are made of tough, flexible cartilage, which maintains the shape of the trachea and prevents it from collapsing under the pressure changes caused by breathing. This allows for the smooth flow of air into and out of the lungs.
6.
The Adam's apple
Correct Answer
C. Refers to the adult male thyroid cartilage
Explanation
The Adam's apple refers to the adult male thyroid cartilage. This cartilage is located in the front of the neck and becomes more prominent during puberty in males. It is more noticeable in males due to the effects of testosterone, which causes the cartilage to grow larger and protrude, creating the characteristic "Adam's apple" appearance.
7.
The bronchi, bronchioles, and alveoli are
Correct Answer
C. Collectively referred to as the bronchial tree
Explanation
The bronchi, bronchioles, and alveoli are collectively referred to as the bronchial tree. This term is used to describe the entire network of airways in the lungs that are involved in the exchange of respiratory gases. The bronchial tree starts with the bronchi, which branch out into smaller bronchioles, and finally end in tiny air sacs called alveoli. The exchange of oxygen and carbon dioxide between the lungs and the bloodstream occurs in the alveoli. Therefore, all of these structures play a crucial role in the exchange of respiratory gases.
8.
Which of the following statements is true of the right bronchus?
Correct Answer
A. Food and small objects are more likely to be aspirated into the right bronchus because it is more vertical and larger than the left bronchus
Explanation
The right bronchus is more vertical and larger than the left bronchus, making it easier for food and small objects to be aspirated into it. This is because the vertical position and larger size create a more direct and wider pathway for foreign objects to enter the right bronchus.
9.
The diameter of the bronchioles determines the
Correct Answer
C. Air flow through the bronchioles to the alveoli
Explanation
The diameter of the bronchioles determines the air flow through the bronchioles to the alveoli. The bronchioles are small airways in the lungs that branch out from the bronchi. The diameter of the bronchioles can be constricted or dilated, which affects the amount of air that can flow through them. When the bronchioles are constricted, the air flow is reduced, while when they are dilated, the air flow is increased. This has a direct impact on the amount of air that reaches the alveoli, which are tiny air sacs where gas exchange occurs in the lungs. Therefore, the diameter of the bronchioles plays a crucial role in determining the air flow to the alveoli.
10.
Pulmonary edema refers to the collection of fluid in and around this structure
Correct Answer
C. Alveoli
Explanation
Pulmonary edema refers to the collection of fluid in and around the alveoli. The alveoli are tiny air sacs in the lungs where oxygen is exchanged for carbon dioxide during respiration. When fluid accumulates in the alveoli, it impairs the ability of the lungs to oxygenate the blood and can cause symptoms such as shortness of breath and coughing. This condition can be caused by various factors, including heart failure, lung infections, or exposure to certain toxins.
11.
Contraction of the diaphragm
Correct Answer
A. Increases thoracic volume
Explanation
When the diaphragm contracts, it moves downward, causing an increase in the volume of the thoracic cavity. This expansion of the thoracic cavity leads to an increase in intrathoracic volume. As a result, the intrapleural pressure decreases, creating a pressure gradient that helps to keep the lungs inflated. Additionally, the increase in thoracic volume also leads to an increase in intrapulmonic pressure, which helps to push air out of the lungs during exhalation. Therefore, the contraction of the diaphragm increases thoracic volume, which in turn affects intrapleural and intrapulmonic pressures and causes exhalation.
12.
The lungs contain the
Correct Answer
B. Structures of the bronchial tree
Explanation
The correct answer is structures of the bronchial tree. The bronchial tree refers to the network of tubes and airways that branch out from the trachea and into the lungs. It includes the bronchi, bronchioles, and alveoli, which are responsible for transporting air in and out of the lungs and facilitating gas exchange. The other options mentioned, such as inspiratory and expiratory neurons, pharynx, larynx, and trachea, and pleural membranes, are not specific to the lungs and do not encompass the entire respiratory system.
13.
Which of the following best describes the visceral and parietal pleura?
Correct Answer
C. Are serous membranes
Explanation
The visceral and parietal pleura are serous membranes. Serous membranes are thin, double-layered membranes that line various body cavities and organs, including the pleural cavity. The visceral pleura covers the surface of the lungs, while the parietal pleura lines the inner surface of the thoracic cavity. Serous membranes secrete a lubricating fluid that allows the organs to move smoothly against each other and reduces friction during breathing.
14.
What normally "lives" in the intrapleural space?
Correct Answer
C. Serous fluid
Explanation
The intrapleural space is the space between the two layers of the pleura, which are the membranes that surround the lungs. It is filled with serous fluid, a clear, watery fluid that acts as a lubricant, reducing friction between the lungs and the chest wall during breathing. This fluid helps to maintain the integrity and function of the pleural membranes, allowing for smooth and efficient movement of the lungs.
15.
Which of the following makes it easier for the alveoli to open?
Correct Answer
C. Surfactant
Explanation
Surfactant is a substance that reduces the surface tension of the fluid lining the alveoli in the lungs. This reduction in surface tension allows the alveoli to open more easily during inhalation, facilitating the exchange of oxygen and carbon dioxide. Water, serous fluid, and mucus do not have the same effect on surface tension and therefore do not make it easier for the alveoli to open.
16.
A deficiency of surfactant causes
Correct Answer
A. Alveolar collapse
Explanation
A deficiency of surfactant causes alveolar collapse because surfactant is a substance that reduces surface tension in the alveoli of the lungs. Without enough surfactant, the alveoli become more prone to collapsing, leading to decreased lung function and difficulty in maintaining proper gas exchange. This can result in respiratory distress and other complications.
17.
If intrapleural pressure equals or exceeds intrapulmonic pressure
Correct Answer
B. The lung collapses
Explanation
When the intrapleural pressure (pressure in the space between the lungs and the chest wall) equals or exceeds the intrapulmonic pressure (pressure inside the lungs), it can lead to lung collapse. This occurs because the pressure inside the lungs is not sufficient to keep them inflated, causing them to collapse. This can be caused by various factors such as pneumothorax (air in the pleural space), atelectasis (collapsed lung tissue), or other conditions that increase intrapleural pressure. Lung collapse can result in impaired gas exchange and respiratory function.
18.
Which of the following does not occur on inhalation?
Correct Answer
D. Pressure within the intrapleural space becomes positive
Explanation
During inhalation, the diaphragm contracts, causing it to move downward, and the thoracic volume increases. This expansion of the thoracic cavity creates a negative pressure within the intrapleural space, which helps to keep the lungs inflated. As a result, the pressure within the intrapleural space does not become positive during inhalation.
19.
Which of the following occurs on exhalation?
Correct Answer
D. Thoracic volume decreases
Explanation
During exhalation, the thoracic volume decreases. This is because the diaphragm and intercostal muscles relax, causing the chest cavity to decrease in size. As the chest cavity decreases, the pressure inside increases, pushing the air out of the lungs. This process is known as exhalation or expiration.
20.
Which of the following describes Boyle's law?
Correct Answer
C. An increase in thoracic volume decreases intrapulmonic pressure
Explanation
Boyle's law states that when the volume of a gas increases, the pressure of the gas decreases, assuming the temperature remains constant. This means that as the thoracic volume increases, the intrapulmonic pressure (pressure within the lungs) decreases. Therefore, the correct answer is "an increase in thoracic volume decreases intrapulmonic pressure."
21.
Which of the following is not true of the salivary glands?
Correct Answer
B. Secrete the most important of the digestive enzymes
Explanation
The salivary glands secrete various digestive enzymes, but they do not secrete the most important ones. The most important digestive enzymes are produced by the pancreas, such as amylase, lipase, and protease. The salivary glands primarily secrete ptyalin, which is an enzyme that helps break down carbohydrates in the mouth.
22.
The epiglottis
Correct Answer
A. Covers the glottis, thereby preventing the entrance of food and water into the respiratory structures
Explanation
The epiglottis is a flap of cartilage located at the base of the tongue. Its main function is to cover the glottis, which is the opening to the trachea, during swallowing. This action prevents food and water from entering the respiratory structures, such as the lungs, and instead directs them into the esophagus and down to the stomach. This mechanism helps to protect the respiratory system from aspiration, which is the inhalation of foreign substances into the lungs that can cause choking or respiratory infections.
23.
The esophagus
Correct Answer
C. Is a hollow tube that carries food from the pHarynx to the stomach
Explanation
The correct answer is that the esophagus is a hollow tube that carries food from the pharynx to the stomach. This means that the esophagus serves as a passage for food to travel from the throat to the stomach for digestion. It does not secrete proteolytic enzymes or intrinsic factor, and while it does have sphincters at each end (the lower esophageal sphincter and the pyloric sphincter), these are not mentioned in the question stem.
24.
The stomach
Correct Answer
D. Delivers chyme to the duodenum at the proper rate
Explanation
The stomach delivers chyme to the duodenum at the proper rate. Chyme is the mixture of partially digested food and gastric juices that is produced in the stomach. It is important for the stomach to deliver chyme to the duodenum at the appropriate rate to ensure efficient digestion and absorption of nutrients. If the rate is too fast, the duodenum may not be able to properly process the chyme. If the rate is too slow, it can lead to delayed digestion and absorption. Therefore, the stomach plays a crucial role in regulating the delivery of chyme to the duodenum at the proper rate.
25.
With which word is deglutition most associated?
Correct Answer
C. Swallowing
Explanation
Deglutition is the medical term for the process of swallowing. It involves the movement of food or liquid from the mouth, through the throat, and into the esophagus. Therefore, deglutition is most closely associated with the word "swallowing."
26.
Paralytic ileus is the
Correct Answer
C. Slowing or cessation of peristalsis
Explanation
Paralytic ileus refers to the slowing or cessation of peristalsis, which is the wave-like movement of the muscles in the digestive system that propels food through the intestines. This condition can occur due to various factors such as surgery, medication side effects, or underlying medical conditions. When peristalsis is impaired, food and fluids cannot move through the digestive system properly, leading to symptoms such as bloating, abdominal pain, and constipation. Prompt medical intervention is necessary to address the underlying cause and restore normal bowel function.
27.
Which of the following best describes the omentum and the mesentery?
Correct Answer
C. Serous membrane
Explanation
The omentum and the mesentery are both serous membranes. Serous membranes are thin, double-layered membranes that line the walls of body cavities and cover the organs within those cavities. They secrete a lubricating fluid that allows organs to move smoothly against each other. The omentum is a fold of the peritoneum (the serous membrane lining the abdominal cavity) that connects the stomach to other abdominal organs, while the mesentery is a fold of the peritoneum that attaches the intestines to the abdominal wall. Therefore, the best description for the omentum and the mesentery is that they are serous membranes.
28.
Which of the following is not a function of the stomach?
Correct Answer
C. Synthesis of plasma proteins especially albumin
Explanation
The stomach is not responsible for the synthesis of plasma proteins, especially albumin. The stomach's main functions include the secretion of intrinsic factor, which is necessary for the absorption of vitamin B12, and the secretion of hydrochloric acid (HCI), which aids in the breakdown of food. Additionally, the stomach helps in the digestion process by delivering chyme, a partially digested mixture of food and gastric juices, to the duodenum, the first part of the small intestine.
29.
Which of the following is not descriptive of bile?
Correct Answer
C. Classified as a lipase
Explanation
Bile is a substance produced by the liver and stored in the gallbladder. It aids in fat digestion by emulsifying fats, which means it breaks them down into smaller droplets to increase their surface area for easier digestion. However, bile itself is not classified as a lipase. Lipases are enzymes that break down fats, while bile helps in their digestion but does not possess enzymatic activity. Therefore, the statement "classified as a lipase" is not descriptive of bile.
30.
Lipases, proteases, and amylases are
Correct Answer
C. Digestive enzymes
Explanation
Lipases, proteases, and amylases are digestive enzymes. These enzymes are responsible for breaking down lipids, proteins, and carbohydrates respectively, into smaller molecules that can be easily absorbed by the body. They play a crucial role in the process of digestion, helping to break down complex food molecules into simpler forms that can be used for energy and other bodily functions.
31.
Fat digestion is accomplished by
Correct Answer
B. Bile and lipase
Explanation
Bile and lipase are involved in fat digestion. Bile, produced by the liver and stored in the gallbladder, helps in the emulsification of fats, breaking them down into smaller droplets. Lipase, produced by the pancreas, is an enzyme that breaks down fats into fatty acids and glycerol, which can be absorbed by the body. Therefore, bile and lipase play crucial roles in the digestion and absorption of dietary fats.
32.
The gallbladder
Correct Answer
A. Contracts in response to cholecystokinin
Explanation
The gallbladder contracts in response to cholecystokinin, a hormone released by the small intestine. This hormone is released in response to the presence of fatty acids and amino acids in the small intestine, signaling the gallbladder to contract and release bile into the digestive system. Bile is essential for the digestion and absorption of fats. Therefore, the contraction of the gallbladder in response to cholecystokinin is an important physiological process for the digestion and absorption of dietary fats.
33.
Which of the following is not a function of the liver?
Correct Answer
C. Secretes cholecystokinin and secretin
Explanation
The liver is responsible for various functions in the body, including the production of blood clotting factors, such as prothrombin, and the production of bile. It also stores fat-soluble vitamins. However, the liver does not secrete cholecystokinin and secretin. These hormones are produced by the small intestine and play a role in the digestion and absorption of nutrients. Therefore, the correct answer is that the liver does not secrete cholecystokinin and secretin.
34.
Which of the following best describes emulsification?
Correct Answer
C. A large fat globule is mechanically broken into smaller fat globules
Explanation
Emulsification refers to the process of breaking down large fat globules into smaller fat globules. This process is primarily mechanical, as it involves the physical disruption and dispersion of fat molecules in a liquid. Emulsification increases the surface area of the fat, allowing for easier digestion and absorption. The other options mentioned in the question, such as the chemical digestion of fats to fatty acids and glycerol or the absorption of fatty acids into the lacteal, are not accurate descriptions of emulsification.
35.
Which of the following organs or structures is essential to life (can't live without it)?
Correct Answer
A. Liver
Explanation
The liver is essential to life because it performs vital functions in the body. It detoxifies harmful substances, produces bile for digestion, stores vitamins and minerals, regulates blood sugar levels, and metabolizes drugs and toxins. Without a functioning liver, the body would not be able to carry out these critical processes necessary for survival.
36.
The pancreas
Correct Answer
A. Secretes the most potent digestive enzymes
Explanation
The pancreas is responsible for secreting digestive enzymes that break down food in the small intestine. These enzymes are highly potent and play a crucial role in the digestion and absorption of nutrients. They help in breaking down carbohydrates, proteins, and fats into smaller molecules that can be easily absorbed by the body. The pancreas also secretes other hormones like CCK and secretin, which regulate the release of digestive enzymes and the production of bile. Therefore, the pancreas is not only important for its exocrine function but also for its endocrine function in regulating digestion.
37.
Which of the following is least related to the appendix?
Correct Answer
D. Regulates the rate at which the contents of the ilium are delivered to the cecum
Explanation
The appendix is a small, finger-shaped pouch that hangs off the end of the cecum, which is the first part of the large intestine. It is not directly involved in regulating the rate at which the contents of the ilium (the last part of the small intestine) are delivered to the cecum. Instead, the appendix is primarily known for its potential to become inflamed and rupture, causing a condition called appendicitis. Therefore, the statement "regulates the rate at which the contents of the ilium are delivered to the cecum" is least related to the appendix.
38.
The duodenum is most concerned with
Correct Answer
B. Digestion and absorption
Explanation
The duodenum is the first part of the small intestine and is primarily responsible for the digestion and absorption of nutrients. It receives partially digested food from the stomach and continues the process of breaking down the food into smaller molecules through the secretion of digestive enzymes. It also absorbs nutrients such as carbohydrates, proteins, fats, vitamins, and minerals into the bloodstream for distribution to the rest of the body. The secretion of intrinsic factor and absorption of vitamin B12 primarily occur in the later part of the small intestine, the ileum. The synthesis of clotting factors and plasma proteins occurs in the liver, while the synthesis of bile and emulsification occur in the liver and gallbladder.
39.
The common bile duct
Correct Answer
C. Empties bile into the duodenum
Explanation
The common bile duct is responsible for emptying bile into the duodenum. Bile is produced by the liver and stored in the gallbladder. When needed, bile is released into the common bile duct and then transported to the duodenum, which is the first part of the small intestine. In the duodenum, bile aids in the digestion and absorption of fats.
40.
Relaxation of the sphincter of Oddi allows
Correct Answer
B. Bile to enter the duodenum from the common bile duct
Explanation
The sphincter of Oddi is a muscular valve that controls the flow of bile and pancreatic juices into the duodenum. When the sphincter relaxes, it allows bile to enter the duodenum from the common bile duct. This is important for the digestion and absorption of fats in the small intestine. Therefore, the relaxation of the sphincter of Oddi facilitates the delivery of bile to the duodenum.
41.
Micturition
Correct Answer
C. Refers to urination
Explanation
Micturition refers to urination. This term is used to describe the process of expelling urine from the body through the urethra. It involves the contraction of the bladder muscles to push urine out of the body. Micturition is a normal physiological process that occurs when the bladder is full and needs to be emptied.
42.
Which of the following is not true of glomerular function?
Correct Answer
D. A decline in FGR causes polyuria and glycosuria
Explanation
A decline in GFR (glomerular filtration rate) causes oliguria, which is a decrease in urine output. This is true because the glomerular filtration rate refers to the amount of fluid filtered by the glomerulus per unit of time, and a decrease in this rate would result in a decreased urine output. On the other hand, a decline in FGR (filtration fraction) causing polyuria and glycosuria is not true. Filtration fraction is the ratio of GFR to renal plasma flow, and a decline in this fraction would not directly cause polyuria (excessive urine output) and glycosuria (presence of glucose in urine).
43.
A deficiency of aldosterone causes a decrease in the tubular reabsorption of sodium and water; causing a significant decrease in blood volume and
Correct Answer
C. Hypotension
Explanation
A deficiency of aldosterone, a hormone produced by the adrenal glands, leads to a decrease in the reabsorption of sodium and water in the tubules of the kidneys. This results in a significant decrease in blood volume, leading to hypotension or low blood pressure. The decrease in blood volume also affects the filtration of waste products in the kidneys, leading to azotemia and uremia. Generalized edema, or swelling, may occur as a result of the decreased reabsorption of water. However, anemia, which is a decrease in red blood cell count, is not directly caused by a deficiency of aldosterone.
44.
Which of the following is least true of aldosterone?
Correct Answer
C. Determines the membrane permeability of the glomeruli to water
Explanation
Aldosterone is a hormone that is responsible for regulating the balance of salt and water in the body. It is a mineralocorticoid, meaning it acts on the kidneys to regulate the levels of minerals, particularly sodium and potassium. It is often referred to as the "salt-retaining" hormone because it promotes the reabsorption of sodium and water in the kidneys, which helps to maintain blood pressure and fluid balance. However, aldosterone does not determine the membrane permeability of the glomeruli to water. This function is primarily regulated by other factors, such as antidiuretic hormone (ADH).
45.
Which of the following urine-making processes occurs last?
Correct Answer
A. Urine concentration by the collecting ducts
Explanation
The urine-making process occurs in several stages, with each process building upon the previous one. Glomerular filtration is the first step, where blood is filtered in the glomerulus to form a filtrate. Reabsorption of Na+ occurs next, where essential substances like water, glucose, and ions are reabsorbed back into the bloodstream. Secretion of K+ follows, where excess potassium ions are actively transported into the filtrate. Finally, urine concentration occurs in the collecting ducts, where water is reabsorbed or excreted based on the body's hydration needs. Therefore, urine concentration by the collecting ducts is the last step in the urine-making process.
46.
Which of the following is true of normal urine?
Correct Answer
C. Urine is normally sterile
Explanation
Urine is normally sterile means that it does not contain any bacteria or other microorganisms. This is because the kidneys and urinary tract are designed to filter out waste products and eliminate them from the body. If urine is not sterile and contains bacteria, it could be a sign of an infection or other underlying health condition.
47.
Which of the following is most likely to cause glucosuria?
Correct Answer
C. Hyperglycemia
Explanation
Glucosuria is the presence of glucose in the urine, which is typically caused by high blood sugar levels. Hyperglycemia refers to abnormally high blood sugar levels, and is most likely to cause glucosuria. Polyuria, uremia, and pyuria are not directly related to glucose levels and are therefore less likely to cause glucosuria.
48.
Renin
Correct Answer
B. Activates angiotensinogen
Explanation
Renin is an enzyme that is secreted by the kidneys, not the posterior pituitary gland. It plays a crucial role in the renin-angiotensin-aldosterone system (RAAS), which regulates blood pressure and fluid balance in the body. Renin acts on angiotensinogen, a protein produced by the liver, and cleaves it to form angiotensin I. Angiotensin I is then converted to angiotensin II by the action of angiotensin-converting enzyme (ACE). Angiotensin II is a potent vasoconstrictor, meaning it narrows blood vessels, leading to an increase in blood pressure. Therefore, the correct answer is that renin activates angiotensinogen.
49.
Which of the following is true of angiotensin II?
Correct Answer
C. Is a potent vasoconstictor
Explanation
Angiotensin II is a potent vasoconstrictor. Vasoconstriction refers to the narrowing of blood vessels, which leads to an increase in blood pressure. Angiotensin II acts on smooth muscle cells in the walls of blood vessels, causing them to constrict and reducing the diameter of the blood vessels. This constriction increases the resistance to blood flow, resulting in an elevation in blood pressure.
50.
Most tubular reabsorption takes place
Correct Answer
D. Across the proximal tubule
Explanation
Tubular reabsorption refers to the process by which substances are transported from the tubular fluid back into the bloodstream. The majority of tubular reabsorption takes place across the proximal tubule, which is the first segment of the renal tubule. This is because the proximal tubule has a high density of transporters that actively reabsorb important substances, such as glucose, amino acids, and electrolytes, back into the bloodstream. Therefore, the correct answer is across the proximal tubule.