Match the following parts of a nephron with their function: (a) Descending limb of Henle's loop (b) Proximal convoluted tubule (c) Ascending limb of Henle's loop (d) Distal convoluted tubule (i) Reabsorption of salts only (ii) Reabsorption of water only (iii) Conditional reabsorption of sodium ion and water (iv) Reabsorption of ion, water and organic nutrients. Select the correct option from the following
Answer: (B) (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii). Answer: (B) (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii).
- A.(a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)
- B.(a)-(ii), (b)-(iv), (c)-(i), (d)-(iii)✓
- C.(a)-(i), (b)-(iv), (c)-(ii), (d)-(iii)
- D.(a)-(iv), (b)-(i), (c)-(iii), (d)-(ii)
Correct Answer
(B) (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii)
Solution & Explanation
Answer: (B) (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii). Solution: The descending limb of Henle's loop is permeable to water but almost impermeable to electrolytes, so it reabsorbs water only (a-ii). The PCT reabsorbs nearly all essential nutrients and most electrolytes and water, i.e. ions, water and organic nutrients (b-iv). The ascending limb is impermeable to water but transports electrolytes, so reabsorption of salts only (c-i). The DCT carries out conditional reabsorption of Na+ and water (d-iii). This gives a-ii, b-iv, c-i, d-iii. NCERT Reference: Ch 16, p.209, line(s) 38-45 — "The descending limb of loop of Henle is permeable to water but almost impermeable to electrolytes... Conditional reabsorption of Na+ and water takes place in this segment."