Question

Most electrolyte reabsorption by the renal tubules is ________

A) not limited by a transport maximum
B) hormonally controlled in distal tubule segments
C) accomplished after the nephron loop is reached
D) in the distal convoluted tubule

Answer 1

Most electrolyte reabsorption by the renal tubules is hormonally controlled in distal tubule segments (option B).

Step-by-step explanation:

In the distal convoluted tubule (DCT), which is the latter part of the renal tubule, hormonal control is significant for managing the reabsorption of water and key electrolytes. Hormones such as aldosterone and antidiuretic hormone (ADH) play a crucial role here.

However, it's essential to note that while a substantial amount of reabsorption occurs in the proximal convoluted tubule (PCT) and the loop of Henle, by the time the forming urine reaches the distal convoluted tubule, approximately 80 percent of filtered water has already been recovered. The DCT and the collecting ducts then fine-tune the process, often recuperating another 10-15 percent of the water under the influence of hormones, which may significantly alter the final urine concentration depending on the body's hydration status.

Thus, the correct option is B.