A&p 2 Urinary & Respiratory

Alcohol acts as a diuretic because it inhibits the release of ADH. ADH, or antidiuretic hormone, is responsible for regulating the amount of water reabsorbed by the kidney tubules. When alcohol is consumed, it suppresses the release of ADH, leading to decreased reabsorption of water by the kidneys. As a result, more water is excreted in the urine, causing increased urine production and the diuretic effect of alcohol.

Creatine is not reabsorbed by the proximal convoluted tubule. The proximal convoluted tubule is responsible for reabsorbing most of the filtered substances, such as glucose, sodium ions (Na+), and potassium ions (K+), back into the bloodstream. However, creatine, which is a waste product of muscle metabolism, is not reabsorbed and is instead excreted in the urine. This helps to regulate the levels of creatine in the body and prevent its accumulation.

The respiratory system is responsible for the exchange of gases between the body and the environment. Pulmonary ventilation refers to the process of breathing, where air is inhaled and exhaled. External respiration involves the exchange of oxygen and carbon dioxide between the lungs and the blood. Pulmonary respiration refers to the exchange of gases between the lungs and the surrounding tissues. Transport of respiratory gases, on the other hand, refers to the movement of oxygen and carbon dioxide through the bloodstream to and from the tissues. This process is primarily carried out by the circulatory system, specifically the cardiovascular system. Therefore, transport of respiratory gases is not a functional process performed by the respiratory system.

The correct answer is "pressure within the alveoli of the lungs." Intrapulmonary pressure refers to the pressure within the alveoli, which are small air sacs in the lungs where gas exchange takes place. This pressure changes during the respiratory cycle, increasing during inspiration and decreasing during expiration. It is essential for the movement of air in and out of the lungs.

The vital capacity represents the total volume of exchangeable air in the lungs. It is the maximum amount of air that can be exhaled after a maximum inhalation. It is calculated by adding the tidal volume, inspiratory reserve volume, and expiratory reserve volume. The tidal volume is the amount of air inhaled and exhaled during normal breathing, while the inspiratory capacity is the maximum amount of air that can be inhaled after a normal exhalation. The expiratory reserve volume is the additional amount of air that can be exhaled forcefully after a normal exhalation. Therefore, the vital capacity encompasses all of these volumes and represents the total volume of exchangeable air.

When carbon dioxide enters the red blood cells, it combines with water to form carbonic acid. Carbonic acid then dissociates into bicarbonate ions and hydrogen ions. The majority of carbon dioxide is carried in the blood as bicarbonate ions in the plasma. This allows for efficient transport of carbon dioxide from the tissues to the lungs, where it can be eliminated through exhalation.

At 28 weeks, the respiratory system of a premature baby is developed enough for survival. By this stage, the lungs have developed the necessary structures to support breathing, such as the alveoli and surfactant production. While a premature baby may still have some difficulty breathing, they have a higher chance of survival compared to earlier stages of development.

When an individual goes from a low to a high altitude, the concentration of oxygen and/or total atmospheric pressure decreases. This decrease in oxygen availability triggers the release of erythropoietin hormone, which stimulates the production of red blood cells (erythrocytes) in the bone marrow. The increase in erythrocyte count helps to compensate for the lower oxygen levels at high altitudes, ensuring that the body receives enough oxygen for proper functioning.

The renal corpuscle is composed of the glomerulus and the Bowman's capsule, and it is responsible for the initial filtration of blood in the kidneys. The podocyte is a specialized cell that forms the filtration barrier in the glomerulus. A fenestrated capillary is a type of blood vessel that allows for efficient filtration due to its porous nature. An efferent arteriole is the blood vessel that carries blood away from the glomerulus. On the other hand, the vasa recta is not directly associated with the renal corpuscle. It is a network of blood vessels that surrounds the loop of Henle in the kidney, playing a role in maintaining the osmotic gradient in the medulla.

The statement "respiratory rate is lowest in newborn infants" is incorrect. In fact, the respiratory rate in newborn infants is relatively higher compared to adults. Newborns typically have a respiratory rate of around 30-60 breaths per minute, whereas adults have a lower respiratory rate of around 12-20 breaths per minute.

The correct answer is transitional because the urinary bladder is made up of transitional epithelium. This type of epithelium is specialized to stretch and accommodate changes in volume, which is important for the bladder's function of storing and releasing urine. Transitional epithelium is found in organs that need to expand and contract, such as the urinary bladder, ureters, and urethra. It is characterized by multiple layers of cells that can change shape from squamous (flattened) to cuboidal (rounded) depending on the degree of stretching.

The decrease in lactic acid levels does not influence the increase in ventilation that occurs as exercise is initiated. During exercise, ventilation increases to meet the increased demand for oxygen and removal of carbon dioxide. This increase in ventilation is primarily regulated by the respiratory center in the brain, which is stimulated by various factors such as psychic stimuli, proprioceptors, and simultaneous cortical motor activation of the skeletal muscles and respiratory center. Lactic acid levels are not directly involved in regulating ventilation during exercise.

When a diver holds their breath upon ascent, the pressure decreases rapidly as they rise to the surface. This causes the air in their lungs to expand, potentially leading to the formation of gas emboli. Gas emboli are bubbles of gas that can block blood vessels and cause serious health issues, such as decompression sickness or arterial gas embolism. It is important for divers to exhale continuously during ascent to prevent the buildup of pressure in the lungs and minimize the risk of gas emboli.

The glomerulus is a network of capillaries located in the kidney. Unlike other capillaries in the body, the glomerulus is drained by an efferent arteriole. This means that the blood that enters the glomerulus through the afferent arteriole exits through the efferent arteriole. This unique drainage system helps to maintain the high pressure within the glomerulus, which is necessary for the process of filtration. The efferent arteriole also plays a role in regulating blood flow and pressure within the glomerulus, which is important for proper kidney function.

The filtration membrane is a structure in the kidney responsible for filtering waste products and excess fluid from the blood. It is composed of three layers: the glomerular endothelium, podocytes, and the basement membrane. The glomerular endothelium is a layer of cells that line the glomerular capillaries, allowing for the passage of small molecules. Podocytes are specialized cells that wrap around the capillaries and help regulate the filtration process. The basement membrane is a thin layer of extracellular matrix that acts as a physical barrier. Renal fascia, on the other hand, is a connective tissue that surrounds and supports the kidney, but it is not part of the filtration membrane.

The statement that resistance to air flow increases due to the increase in cross-sectional diameter is not true. In reality, resistance to air flow decreases as the cross-sectional diameter increases. This is because a larger diameter allows for a greater volume of air to flow through the respiratory tract, reducing the resistance to airflow.

The correct statement about the pharynx is that the auditory tube drains into the nasopharynx. The auditory tube, also known as the Eustachian tube, connects the middle ear to the nasopharynx and helps equalize pressure between the middle ear and the atmosphere. This allows for proper functioning of the ear and helps prevent ear infections.

The larynx contains various structures, including the thyroid cartilage, which is a prominent feature commonly referred to as the Adam's apple. This cartilage helps protect the vocal cords and provides support to the larynx. It is the largest cartilage in the larynx and can be easily felt in the front of the neck. The other structures mentioned, such as the true vocal folds and false vocal folds, are also present in the larynx and play important roles in producing sound and protecting the airway.

An increase in the permeability of the cells of the collecting tubule to water is due to an increase in the production of ADH. ADH, or antidiuretic hormone, plays a crucial role in regulating the body's water balance. When ADH levels increase, it causes the collecting tubules in the kidneys to become more permeable to water, allowing more water to be reabsorbed into the bloodstream. This helps to conserve water and prevent excessive water loss through urine.

The stretching of the bladder wall acts as the trigger for the initiation of micturition (voiding). When the bladder fills with urine, the walls of the bladder stretch, and this stretch is detected by specialized receptors called stretch receptors. These receptors send signals to the brain, which then initiates the micturition reflex. This reflex involves the relaxation of the internal urethral sphincter and contraction of the bladder muscles, leading to the expulsion of urine from the body. Therefore, the stretching of the bladder wall is the primary factor that initiates the process of micturition.

The given information states that the concentration of the amino acid in the blood is higher than its Tm (transport maximum). This indicates that the capacity for reabsorption of the amino acid by the tubule cells has been exceeded. As a result, the excess amino acid cannot be fully reabsorbed and will instead appear in the urine.

The correct sequence for the formation of a drop of urine to its elimination from the body is as follows: First, the nephron filters waste materials from the blood. Then, the collecting duct receives the filtered urine from multiple nephrons. Next, the minor calyx collects the urine from the collecting ducts. After that, the major calyx collects urine from multiple minor calyces. Then, the urine passes through the ureter, which transports it from the kidney to the bladder. Finally, the urine is eliminated from the body through the urethra.

CO2 is mostly transported in the blood in the form of bicarbonate ions (HCO3-) rather than being dissolved in the blood plasma or carried by red blood cells (RBCs). Only a small fraction of CO2 is dissolved in the blood plasma, while the majority is converted to bicarbonate ions in the red blood cells and transported to the lungs to be exhaled. Therefore, the statement that more CO2 dissolves in the blood plasma that is carried in the RBCs is incorrect.

The correct answer is surface tension from pleural fluid and negative pressure in the pleural cavity. The pleural cavity is the space between the lungs and the thorax wall, and it is filled with pleural fluid. The surface tension created by this fluid helps to hold the lungs against the thorax wall. Additionally, the pleural cavity has a negative pressure, which means that the pressure inside the cavity is lower than the atmospheric pressure. This negative pressure also contributes to keeping the lungs attached to the thorax wall.

The arcuate artery lies on the boundary between the cortex and medulla of the kidney.

The ventral respiratory group is responsible for generating nerve impulses that result in inspiration. It is a group of neurons located in the medulla oblongata of the brainstem. These neurons send signals to the muscles involved in breathing, causing them to contract and initiate the inhalation process. Therefore, when nerve impulses originate from the ventral respiratory group, it triggers the inspiration phase of breathing.

The correct statement about ureters is that they are capable of peristalsis like that of the gastrointestinal tract. Peristalsis refers to the wave-like muscle contractions that help propel substances through the digestive system. Similarly, the ureters have smooth muscle in their walls that contract in a coordinated manner to push urine from the kidneys to the bladder. This peristaltic movement helps ensure the unidirectional flow of urine and prevents backflow.

The correct answer describes the histology of the ureters as being trilayered, consisting of the mucosa, muscularis, and adventitia. This means that the ureters have three distinct layers: the innermost mucosa, which lines the lumen and helps with absorption and secretion; the middle muscularis, which is responsible for peristaltic contractions to propel urine; and the outermost adventitia, which provides support and protection to the ureters. This trilayered structure is important for the efficient transport of urine from the kidneys to the bladder.

The descending limb of the loop of Henle is not permeable to water, but it is freely permeable to sodium and urea. As the fluid moves down into the medulla, it becomes more concentrated because water is not able to leave the tubule through the descending limb. This concentration gradient is important for the reabsorption of water in the collecting duct, as it allows for water to be pulled out of the tubule by osmosis.

Diabetes insipidus is a disease caused by inadequate secretion of antidiuretic hormone (ADH) by the pituitary glands. This hormone is responsible for regulating the amount of water reabsorbed by the kidneys. When there is a deficiency of ADH, the kidneys are unable to concentrate urine, leading to excessive urination (polyuria). Therefore, the symptoms described in the question align with diabetes insipidus. Diabetes mellitus is a different condition characterized by high blood sugar levels, diabetic acidosis refers to a complication of diabetes mellitus, and coma is a severe state of unconsciousness that can occur in various medical conditions.

The pleura is a double-layered membrane that surrounds the lungs and lines the chest cavity. Its main roles include allowing the lungs to inflate and deflate without friction, helping to divide the thoracic cavity into three chambers, and helping to limit the spread of local infections. However, it does not directly aid in blood flow to and from the heart. The heart sits between the lungs, but its blood flow is facilitated by the coronary arteries and veins, not the pleura.

The given answer is incorrect because eliminating solid, undigested wastes and excreting carbon dioxide, water, salts, and heat is a function of the urinary system. The urinary system is responsible for filtering waste products from the blood and excreting them in the form of urine. It also helps regulate the balance of water, electrolytes, and pH in the body.

If one says that the clearance value of glucose is zero, it means that normally all the glucose is reabsorbed. This suggests that the kidneys are effectively reabsorbing all the glucose from the blood and preventing its excretion in the urine.

The mechanism that establishes the medullary osmotic gradient depends most on the permeability properties of the loop of Henle. The loop of Henle plays a crucial role in reabsorbing water and ions from the filtrate, creating a concentration gradient in the medulla of the kidney. This allows for the reabsorption of water in the collecting duct and the regulation of urine concentration. The glomerular filtration membrane is responsible for filtering blood and does not directly contribute to the establishment of the osmotic gradient. The collecting duct and distal convoluted tubule also play roles in reabsorption and concentration, but they are not as influential as the loop of Henle.

The forces that act to pull the lungs away from the thorax wall and collapse the lungs are the neural tendency for the lungs to recoil and the surface tension of the alveolar fluid. The neural tendency for the lungs to recoil refers to the natural elasticity of the lung tissue, which causes it to want to shrink back to its original size. The surface tension of the alveolar fluid refers to the cohesive forces between the molecules of the fluid lining the alveoli, which creates a force that pulls the alveoli inward and collapses the lungs.

A 50% oxygen saturation level of blood returning to the lungs might indicate an activity level higher than normal because during increased physical activity, the body requires more oxygen to meet the increased energy demands. As a result, the oxygen saturation level in the blood decreases as more oxygen is extracted by the tissues. Therefore, a lower oxygen saturation level suggests that the body is utilizing more oxygen, indicating a higher activity level.

As alveolar surface tension increases, additional muscle action will be required. This is because alveolar surface tension refers to the force that exists at the air-liquid interface in the alveoli, which can make it harder for the alveoli to expand during inhalation. In order to overcome this increased surface tension, additional muscle action is needed to expand the alveoli and allow for proper ventilation.

The number of red blood cells is not a factor that promotes oxygen binding to and dissociation from hemoglobin. Oxygen binding to hemoglobin is primarily influenced by the partial pressure of oxygen, which determines the concentration gradient for oxygen to diffuse into the red blood cells. Temperature also affects oxygen binding, as higher temperatures promote oxygen release from hemoglobin. Additionally, the partial pressure of carbon dioxide affects oxygen binding, as an increase in carbon dioxide decreases the affinity of hemoglobin for oxygen, promoting oxygen release to tissues. However, the number of red blood cells does not directly affect oxygen binding or dissociation.

The macula densa cells are specialized cells located in the kidney tubules that monitor the solute content of the filtrate. When the solute content of the filtrate changes, the macula densa cells respond by releasing chemical signals that regulate the function of the nearby juxtaglomerular cells. These juxtaglomerular cells then release renin, which initiates a cascade of events leading to the regulation of blood pressure and fluid balance in the body. Therefore, the macula densa cells play a crucial role in maintaining homeostasis by responding to changes in solute content of the filtrate.

Podocyte cells are not a part of the juxtaglomerular apparatus. The juxtaglomerular apparatus is a specialized region in the kidney that helps regulate blood pressure and filtration. It consists of three main components: granular cells, macula densa, and mesangial cells. Granular cells are located in the walls of the afferent arterioles and secrete renin, an enzyme involved in blood pressure regulation. Macula densa cells are located in the distal convoluted tubule and monitor the concentration of sodium chloride in the filtrate. Mesangial cells are located in the glomerulus and help support the structure and function of the glomerulus. However, podocyte cells are not part of the juxtaglomerular apparatus and are instead found in the filtration barrier of the glomerulus.

Tubular reabsorption is the process by which substances, including creatinine, are reabsorbed from the tubules of the kidneys back into the bloodstream. This process typically occurs through active mechanisms, which means that it requires energy and involves movement against an electrical and/or chemical gradient. In other words, substances are moved from an area of lower concentration (the tubule) to an area of higher concentration (the blood). This active reabsorption helps regulate the balance of substances in the body and is not a way to get rid of waste.

If the capsular hydrostatic pressure were increased above normal, it would result in a decrease in net filtration. This is because an increase in capsular hydrostatic pressure would oppose the movement of fluid out of the glomerulus and into the Bowman's capsule. The higher pressure inside the capsule would push back against the filtration process, reducing the overall amount of fluid that is filtered. Therefore, the net filtration would decrease in this scenario.

Voluntary cortical control refers to the ability of an individual to consciously control their breathing rate and depth. This means that a person can choose to breathe faster or slower and take deeper or shallower breaths. Factors such as stress, physical activity, and emotions can influence this voluntary control. The other factors mentioned, thalamic control, stretch receptors in the alveoli, and composition of alveolar air, do not directly involve conscious control and are more related to automatic regulation of breathing.

Secondary active transport is the correct answer because it involves the movement of molecules against their concentration gradient, utilizing the energy from the electrochemical gradient of another molecule. In the case of reabsorption of glucose and amino acids in the filtrate, they are transported across the cell membrane against their concentration gradient, using the energy from the sodium gradient created by the sodium-potassium pump. This process is known as secondary active transport because it relies on the energy stored in the sodium gradient, which is established by primary active transport.

The loop of Henle is responsible for forming a large volume of very dilute urine or a small volume of very concentrated urine. This is achieved through the process of countercurrent multiplication, where the loop creates a concentration gradient in the medulla of the kidney. As filtrate flows through the descending limb of the loop, water is reabsorbed passively, leading to a concentrated filtrate. In the ascending limb, electrolytes are actively reabsorbed, further concentrating the filtrate. This allows the kidney to regulate the concentration of urine based on the body's hydration needs.

The statement "the pons is thought to be instrumental in the smooth transition from inspiration to expiration" is correct. The pons, a region in the brainstem, plays a crucial role in regulating the transition between inspiration (breathing in) and expiration (breathing out). It contains neurons that control the timing and coordination of respiratory muscles, allowing for a smooth transition between these two phases of the breathing cycle.

Substances that are extremely complex molecules are not a reason why they are either not reabsorbed or incompletely reabsorbed from the nephron. The complexity of a molecule does not directly affect its reabsorption. The main factors that determine reabsorption include the presence of carriers to transport the substance, lipid solubility to pass through cell membranes, and size to pass through fenestrations (pores).

The correct statement about the nephrons is that the parietal layer of the glomerular capsule is simple squamous epithelium.

The given statement "pressure gradient equals gas flow over resistance" is not possible because the pressure gradient is defined as the difference in pressure between two points, while gas flow is the movement of gas from one point to another. Resistance is a measure of how difficult it is for the gas to flow. Therefore, the pressure gradient cannot be equal to the gas flow divided by resistance.

Electrolyte reabsorption refers to the process by which the kidneys reabsorb electrolytes from the urine back into the bloodstream. In the renal tubules, specifically in the distal convoluted tubule, electrolyte reabsorption is not limited by the maximum transport capacity (Tm). This means that the reabsorption of electrolytes can occur at a constant rate regardless of their concentration in the tubular fluid. However, the reabsorption of electrolytes in the distal tubule segments is hormonally controlled. This means that hormones, such as aldosterone, regulate the reabsorption of electrolytes in these segments based on the body's needs. Therefore, the correct answer is that electrolyte reabsorption is hormonally controlled in distal tubule segments.

The correct answer is impermeability of the collecting tubule to water. In order to excrete dilute urine, the collecting tubule needs to be impermeable to water, meaning that water cannot pass through its walls and be reabsorbed back into the bloodstream. This allows water to remain in the urine, resulting in a higher volume of dilute urine being excreted. If the collecting tubule was permeable to water, water would be reabsorbed back into the bloodstream, resulting in a lower volume of concentrated urine being excreted.