Which of the following is true of the distal tubule?
a. receives urine from the collecting duct
b. responds to aldosterone
c. nephron structure that is primarily concerned with filtration
d. also called Bowman’s capsule
The correct answer and explanation is:
The correct answer is b. responds to aldosterone.
The distal tubule is a key part of the nephron in the kidney, and its main function is to fine-tune the composition of the filtrate that will eventually become urine. It plays an important role in the regulation of electrolyte balance, particularly sodium and potassium, and helps in the regulation of blood pressure and blood volume.
Aldosterone, a hormone produced by the adrenal glands, acts on the distal tubule to increase the reabsorption of sodium and water, while promoting the secretion of potassium. This mechanism helps the body retain water and sodium, which can increase blood volume and blood pressure. The reabsorption of sodium in exchange for potassium is an essential process for maintaining electrolyte balance, and aldosterone is a key regulator of this process.
Option a, “receives urine from the collecting duct,” is incorrect because the distal tubule does not receive urine from the collecting duct; instead, it leads to the collecting duct. The collecting duct is responsible for the final modification of urine, including the concentration of urine, and it receives filtrate from the distal tubule.
Option c, “nephron structure that is primarily concerned with filtration,” is inaccurate because the primary site of filtration in the nephron is the glomerulus, not the distal tubule. The glomerulus filters blood to create the initial filtrate, and the distal tubule is involved in the reabsorption and secretion processes that modify this filtrate.
Option d, “also called Bowman’s capsule,” is incorrect because Bowman’s capsule is a different structure that surrounds the glomerulus and is involved in the initial filtration of blood. The distal tubule is a separate segment of the nephron.