Question

The part of nephron involved in active reabsorption of sodium is

• A. distal convoluted tubule
• B. Proximal convoluted tubule
• C. Bowman’s capsule
• D. descending limb of Henle’s loop

Answer 1

The Correct Option is B

Tubular Reabsorption in the Kidney 

From the Bowman’s capsule, a glomerular filtrate enters the proximal convoluted tubule. In this part of the nephron, absorption of selected materials takes place from the filtrate into the blood of the peritubular capillaries or vasa recta. This process is called tubular reabsorption.

Reabsorption Process:

Reabsorption involves both passive and active transport across the tubular epithelium. About 65 percent of the glomerular filtrate is normally reabsorbed in the proximal convoluted tubule before it reaches the loop of Henle.

Materials Reabsorbed:

The following materials are absorbed during the process of tubular reabsorption:

• Glucose
• Amino acids
• Vitamins
• Hormones
• Sodium (Na⁺)
• Potassium (K⁺)
• Chlorides (Cl^-)
• Phosphates (PO₄³⁻)
• Bicarbonates (HCO₃⁻)
• Much of the water
• Some urea

Mechanism of Reabsorption:

Sodium and potassium ions are reabsorbed by primary active transport, which uses energy to move these ions against their concentration gradients. This ensures the selective reabsorption of essential materials from the filtrate.