Question

What is true about distal convoluted tubule?

• A. ${Na}^{+}$ reabsorption reqires energy
• B. $K^{+}$ reabsorption does not require energy
• C. Ammonia is excreted
• D. Water reabsorption requires energy

Answer 1

Answer: (A)

${Na}^{+}$ reabsorption reqires energy

Conditional reabsorption of Na+ and water takes place in distal convoluted tubule (DCT). As it passes through the distal tubule, the filtrate may become even more dilute. The distal tubule is relatively impermeable to water but actively transports salt out into the interstitial fluid. DCT is also capable of reabsorption of $HC{O}_3$ and selective secretion of hydrogen and potassium ions and $N{H}_3$ to maintain the pH and sodium-potassium balance in blood.