Question 1

Which of the following statements about the reabsorption process in Henle's loop are correct ? (a) The descending limb of Henle's loop is permeable to water but almost impermeable to electrolytes. (b)

Accepted Answer

Based on the NCERT biology textbook: Statement (a) is correct: The descending limb of the loop of Henle is permeable to water but almost impermeable to electrolytes. This causes the filtrate to become concentrated as it moves down. Statement (b) is correct: The primary role of Henle's loop (along with the vasa recta) is to maintain a high osmolarity in the medullary interstitial fluid, which is essential for the concentration of urine. Statement (d) is correct: The ascending limb of Henle's loop

Question 2

The JGA (Juxta Glomerular Apparatus) is a special sensitive region formed by cellular modifications in ____________ related to the same nephron.

Accepted Answer

The Juxta Glomerular Apparatus (JGA) is a special sensitive region formed by cellular modifications in the distal convoluted tubule (DCT) and the afferent arteriole at the location of their contact. The cells of the DCT at this region become modified to form the macula densa, while the smooth muscle cells of the afferent arteriole are modified to form juxtaglomerular (JG) cells, which secrete renin. Answer: Distal convoluted tubule and afferent renal arteriole

Question 3

Arrange the following events occurring in Renin-Angiotensin mechanism in the correct order : A. Increase in blood pressure and Glomerular filtration rate. B. Reabsorption of Na ^ + and water from dist

Accepted Answer

A fall in Glomerular filtration rate (GFR) or glomerular blood pressure activates the juxtaglomerular (JG) cells to release renin. (C) Renin converts angiotensinogen in blood to angiotensin I and further to angiotensin II. (E) Angiotensin II acts as a powerful vasoconstrictor, which increases the glomerular blood pressure. It also activates the adrenal cortex to release Aldosterone. (D) Aldosterone causes the reabsorption of Na ^ + and water from the distal parts of the tubule. (B) This reabsorp

Question 4

Which of the following diagrams is correct with regard to the proximal (P) and distal (D) tubule of the Nephron.

Accepted Answer

During urine formation, the tubular cells secrete substances like H ^ + , K ^ + and ammonia into the filtrate. Tubular secretion is also an important step in urine formation as it helps in the maintenance of ionic and acid base balance of body fluids. PCT Selective secretion of H ^ + , ammonia and K ^ + into the filtrate. DCT Capable of reabsorption of HCO _3^ - and selective secretion of H ^ + , K ^ + and NH _3.

Question 5

Given below are two statements: Statements I: Concentrated urine is formed due to counter current mechanism in nephron. Statement II: Counter current mechanism helps to maintain osmotic gradient in th

Accepted Answer

The correct answer is option (3) as mammals have the ability to produce a concentrated urine. The Henle's loop and vasa recta play a significant role in this. The flow of filtrate in the two limbs of Henle's loop as well as flow of blood through the two limbs of vasa recta are in a counter current pattern. The proximity between the Henle's loop and vasa recta, as well as the counter current in them help in maintaining the increasing osmolarity towards the inner medullary interstitium, i.e., from

Question 6

Choose the correct statement given below regarding juxta medullary nephron.

Accepted Answer

The correct answer is option no, (2) because the length of loop of Henle of juxta medullary nephron is longer than the length of loop of Henle of cortical nephron and runs deep into medulla. Option (1) is incorrect because renal corpuscle of juxta medullary nephron lies in inner cortical region. Option (3) is incorrect as juxta medullary nephrons are lesser in number than cortical nephrons. Option (4) is incorrect as juxta medullary nephron are not present in columns of Bertini.

Question 7

Given below are two statements : Statement I : In the nephron, the descending limb of loop of Henle is impermeable to water and permeable to electrolytes. Statement II : The proximal convoluted tubule

Accepted Answer

Correct answer is option (1) because Statement I is false as the descending limb of loop of Henle is permeable to water and almost impermeable to electrolytes. Statement II is false as proximal convoluted tubule is lined by simple cuboidal brush border epithelium which increases the surface area for reabsorption.

Question 8

Diuresis is prevented by:

Accepted Answer

The correct answer is option (4) because, - Diuresis is prevented by vasopressin or anti-diuretic hormone from neurohypophysis or posterior pituitary. When there is excessive loss of fluid from the body the secretion of, ADH facilitates water reabsorption from latter part of renal tubules. - Option (1) is incorrect because renin from JG cells convert angiotensinogen in blood to angiotensin I and further to angiotensin II; which is a powerful vasoconstrictor and increases the glomerular blood pre

Excretory Products and their Elimination — Previous Year Questions & Solutions