Question

Selective reabsorption of components in glomerular filtrate is regulated in these parts of nephron

• A. Proximal convoluted tubule and distal convoluted tubule
• B. Loop of Henle and distal convoluted tubule
• C. Distal convoluted tubule and collecting duct
• D. Proximal convoluted tubule and Loop of Henle

Hint:

{PCT:} Site of maximum reabsorption (70-80%). {DCT/CD:} Site of conditional (regulated) reabsorption.

Answer 1

The Correct Option is C

Step 1: Understanding Reabsorption Types:
Reabsorption in the nephron can be classified into two types:

• Obligatory Reabsorption: Occurs in the Proximal Convoluted Tubule (PCT). It is constant and not hormonally regulated (e.g., bulk reabsorption of water and nutrients).
• Facultative (Regulated) Reabsorption: Occurs in the Distal Convoluted Tubule (DCT) and Collecting Duct (CD). This reabsorption is regulated by hormones based on the body's needs.

Step 2: Hormonal Regulation:

• Aldosterone: Acts on DCT and CD to increase $Na^+$ reabsorption and water follows.
• ADH (Vasopressin): Acts on DCT and CD to increase water reabsorption.

Step 3: Conclusion:
Since the question asks for \regulated reabsorption, the answer refers to the DCT and Collecting Duct.