Q31. Which of the following is NOT a function of the urinary system?
a) Regulation of blood pressure
b) Production of digestive enzymes
c) Regulation of blood pH
d) Elimination of metabolic waste
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Correct Answer: b) Production of digestive enzymes
Explanation: The urinary system is not involved in the production of digestive enzymes. Its primary functions include regulation of blood pressure, regulation of blood pH, and elimination of metabolic waste products from the body through the formation and excretion of urine.
Q32. Which structure in the kidney acts as a filtration barrier, allowing small molecules to pass through while retaining larger molecules like proteins?
a) Glomerulus
b) Bowman’s capsule
c) Proximal convoluted tubule
d) Distal convoluted tubule
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Correct Answer: b) Bowman’s capsule
Explanation: Bowman’s capsule, also known as the glomerular capsule, acts as a filtration barrier in the kidney. It surrounds the glomerulus and selectively filters blood plasma, allowing small molecules like water, ions, glucose, and urea to pass through while retaining larger molecules like proteins.
Q33. Which hormone is responsible for stimulating the production of red blood cells in response to low oxygen levels?
a) Aldosterone
b) Antidiuretic hormone (ADH)
c) Erythropoietin
d) Insulin
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Correct Answer: c) Erythropoietin
Explanation: Erythropoietin is a hormone produced by the kidneys in response to low oxygen levels in the blood. It stimulates the production of red blood cells (erythropoiesis) in the bone marrow, helping to increase oxygen-carrying capacity and improve tissue oxygenation.
Q34. What is the name of the process by which excess water and solutes are removed from the blood and added to the tubular fluid for excretion in urine?
a) Glomerular filtration
b) Tubular reabsorption
c) Tubular secretion
d) Urinary excretion
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Correct Answer: c) Tubular secretion
Explanation: Tubular secretion is the process by which excess substances, including waste products, drugs, and ions, are actively transported from the blood into the renal tubules for excretion in urine. It complements filtration and reabsorption processes in the formation of urine.
Q35. Which segment of the nephron is responsible for the reabsorption of water and solutes in a hormonally regulated manner?
a) Glomerulus
b) Loop of Henle
c) Proximal convoluted tubule
d) Distal convoluted tubule
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Correct Answer: b) Loop of Henle
Explanation: The Loop of Henle, particularly its descending limb and ascending limb, is responsible for reabsorbing water and solutes from the tubular fluid in a hormonally regulated manner. It plays a crucial role in establishing the osmotic gradient necessary for urine concentration.
Q36. What is the name of the capillary network that surrounds the renal tubules and participates in the reabsorption and secretion of substances during urine formation?
a) Glomerulus
b) Peritubular capillaries
c) Vasa recta
d) Renal artery
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Correct Answer: b) Peritubular capillaries
Explanation: Peritubular capillaries are a network of capillaries that surround the renal tubules in the cortex of the kidney. They participate in the reabsorption and secretion of substances during urine formation by exchanging solutes and water with the tubular fluid.
Q37. Which of the following substances is a waste product of muscle metabolism that is excreted by the kidneys and gives urine its characteristic yellow color?
a) Urea
b) Bilirubin
c) Hemoglobin
d) Urochrome
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Correct Answer: d) Urochrome
Explanation: Urochrome is a waste product of hemoglobin breakdown and muscle metabolism. It is excreted by the kidneys and gives urine its characteristic yellow color. The intensity of urine color can vary depending on factors such as hydration status and dietary intake.
Q38. Which part of the nephron is responsible for the reabsorption of glucose, amino acids, and other nutrients from the filtrate back into the bloodstream?
a) Glomerulus
b) Bowman’s capsule
c) Proximal convoluted tubule
d) Loop of Henle
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Correct Answer: c) Proximal convoluted tubule
Explanation: The proximal convoluted tubule (PCT) is responsible for the reabsorption of glucose, amino acids, and other nutrients from the glomerular filtrate back into the bloodstream. It is highly convoluted and lined with microvilli to increase surface area for reabsorption.
Q39. Which hormone regulates water balance in the body by increasing water reabsorption in the kidneys?
a) Aldosterone
b) Antidiuretic hormone (ADH)
c) Renin
d) Atrial natriuretic peptide (ANP)
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Correct Answer: b) Antidiuretic hormone (ADH)
Explanation: Antidiuretic hormone (ADH), also known as vasopressin, regulates water balance in the body by increasing water reabsorption in the kidneys. It acts on the collecting ducts to make them more permeable to water, thereby reducing urine volume and conserving water.
Q40. What is the primary nitrogenous waste product excreted by humans?
a) Urea
b) Ammonia
c) Uric acid
d) Creatinine
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Correct Answer: a) Urea
Explanation: Urea is the primary nitrogenous waste product excreted by humans. It is formed in the liver as a result of protein metabolism and is transported to the kidneys for excretion in urine. Urea accounts for the majority of nitrogenous waste eliminated from the body.