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100 questions in this collection · Page 2 of 10
Question 11 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Choose the correct statements regarding the loop of Henle:
I. Reabsorption is maximum in the ascending limb of Henle's loop. II. The descending limb of Henle's loop is permeable to water but almost impermeable to electrolytes. III. The ascending limb is impermeable to water but allows transport of electrolytes actively or passively. IV. As the concentrated filtrate passes upward through the ascending limb, it gets diluted due to the passage of electrolytes to the medullary fluid.
Explanation: Statement I is incorrect because reabsorption is minimum in the ascending limb of Henle's loop. Statements II, III, and IV are correct.
Question 12 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Evaluate these statements concerning the Distal Convoluted Tubule (DCT):
I. Conditional reabsorption of Na+ and water takes place in the DCT segment. II. DCT is capable of reabsorption of HCO3-. III. DCT is capable of selective secretion of hydrogen and potassium ions and NH3. IV. DCT maintains pH and sodium-potassium balance in the blood.
Explanation: All the statements are correct. The DCT carries out conditional reabsorption of Na+ and water, reabsorbs bicarbonate ions, selectively secretes H+, K+, and NH3, and maintains acid-base as well as sodium-potassium balance.
Question 13 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Analyze the statements regarding the collecting duct:
I. The collecting duct is a long duct extending from the cortex of the kidney to the inner parts of the medulla. II. Large amounts of water could be reabsorbed from this region to produce a concentrated urine. III. This segment allows passage of large amounts of urea into the medullary interstitium to keep up the osmolarity. IV. It plays a role in the maintenance of pH and ionic balance of blood by the selective secretion of H+ and K+ ions.
Explanation: Statements I, II, and IV are correct. Statement III is incorrect because only small amounts of urea pass into the medullary interstitium to help maintain medullary osmolarity.
Question 14 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Which of the following statements about the elements of the counter current mechanism are true?
I. The flow of filtrate in the two limbs of Henle's loop is in opposite directions, forming a counter current. II. The flow of blood through the two limbs of vasa recta is in a parallel direction, not a counter current pattern. III. The proximity between Henle's loop and vasa recta helps in maintaining an increasing osmolarity gradient towards the inner medulla. IV. The osmolarity gradient increases from about 300 mOsmol L-1 in the cortex to about 1200 mOsmol L-1 in the inner medulla.
Explanation: Statements I, III, and IV are correct. Statement II is incorrect because blood in the vasa recta also flows in a counter current pattern, which helps maintain the medullary osmotic gradient.
Question 15 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Concerning solute transport in the medullary osmolarity gradient, identify the correct statements:
I. The increasing medullary interstitial gradient is mainly caused by NaCl and urea. II. NaCl is transported by the ascending limb of Henle's loop which is exchanged with the descending limb of vasa recta. III. NaCl is returned to the medullary interstitium by the descending portion of vasa recta. IV. Small amounts of urea enter the thin segment of the ascending limb of Henle's loop which is transported back to the interstitium by the collecting tubule.
Statement I is correct because NaCl and urea are the two major contributors to the medullary osmotic gradient. Statement II is correct because NaCl transported from the ascending limb of Henle's loop is exchanged with the descending limb of the vasa recta. Statement III is incorrect because NaCl is returned to the medullary interstitium by the ascending limb of the vasa recta, not the descending limb. Statement IV is correct because small amounts of urea enter the thin ascending limb of Henle's loop and are recycled back to the medullary interstitium by the collecting tubule.
Question 16 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Read the following statements about urine concentration and kidney performance:
I. Human kidneys can produce urine nearly four times concentrated than the initial filtrate formed. II. The presence of an interstitial osmotic gradient helps in the easy passage of water from the collecting tubule, concentrating the filtrate. III. Vasa recta is highly developed in both cortical and juxtamedullary nephrons to assist the counter current mechanism. IV. The counter current mechanism concentrates the filtrate as it moves up the ascending limb of Henle's loop.
Statements I and II are correct because the kidney can concentrate urine up to about four times the osmolarity of the initial filtrate, and the medullary osmotic gradient promotes water reabsorption from the collecting tubule. Statement III is incorrect because the vasa recta is absent or highly reduced in cortical nephrons. Statement IV is incorrect because the filtrate becomes diluted while ascending the loop of Henle due to electrolyte loss.
Question 17 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Identify the correct statements regarding the hormonal regulation of kidney function by Antidiuretic Hormone (ADH):
I. Osmoreceptors in the body are activated by changes in blood volume, body fluid volume, and ionic concentration. II. Excessive loss of fluid from the body stimulates the hypothalamus to release ADH or vasopressin from the adenohypophysis. III. ADH facilitates water reabsorption from latter parts of the tubule, thereby preventing diuresis. IV. An increase in body fluid volume can switch off the osmoreceptors and suppress the ADH release.
Statements I, III, and IV are correct. Statement II is incorrect because ADH (vasopressin) is released from the neurohypophysis (posterior pituitary), not the adenohypophysis (anterior pituitary).
Question 18 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Consider these statements regarding the hemodynamic and vascular effects of ADH:
I. ADH can affect kidney function by its constrictory effects on blood vessels. II. Vasoconstriction caused by ADH leads to a decrease in systemic blood pressure. III. An increase in blood pressure caused by ADH increases the glomerular blood flow and thereby the GFR. IV. ADH acts as a powerful vasodilator in the renal circulation to increase blood flow.
Statements I and III are correct. Statement II is incorrect because vasoconstriction increases systemic blood pressure. Statement IV is incorrect because ADH (vasopressin) is a vasoconstrictor, not a vasodilator.
Question 19 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Analyze the following statements regarding the Juxtaglomerular Apparatus (JGA) and the Renin-Angiotensin mechanism:
I. A fall in glomerular blood flow, glomerular blood pressure, or GFR can activate the JG cells to release renin. II. Renin converts angiotensinogen in blood to angiotensin I and further to angiotensin II. III. Angiotensin II, being a powerful vasodilator, decreases the glomerular blood pressure. IV. Angiotensin II activates the adrenal cortex to release Aldosterone.
Statements I, II, and IV are correct. Statement III is incorrect because angiotensin II is a powerful vasoconstrictor that increases glomerular blood pressure and stimulates aldosterone secretion.
Question 20 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Identify the correct statements regarding the roles of Aldosterone and Atrial Natriuretic Factor (ANF):
I. Aldosterone causes reabsorption of Na+ and water from the distal parts of the renal tubule. II. The action of aldosterone leads to an increase in blood pressure and GFR. III. An increase in blood flow to the atria of the heart can cause the release of Atrial Natriuretic Factor (ANF). IV. ANF causes vasoconstriction and thereby increases blood pressure to check the renin-angiotensin mechanism.
Statement I is correct because aldosterone promotes Na+ and water reabsorption in the distal renal tubules. Statement II is correct because this increases blood pressure and GFR. Statement III is correct because increased atrial stretch stimulates the release of ANF. Statement IV is incorrect because ANF causes vasodilation and decreases blood pressure, thereby antagonizing the renin-angiotensin mechanism.