Concentration and volume of urine depend on H2O reabsorption where in the nephron?
a) ascending loop of Henle
b) descending loop of Henle
c) distal convoluted tubule and collecting duct
d) proximal convoluted tubule
>>> I think the answer is C but I'm not entirely sure. Could someone let me know what they they the answer is?
To determine where in the nephron the concentration and volume of urine depend on H2O reabsorption, we can review the functions of each segment of the nephron.
a) The ascending loop of Henle is responsible for reabsorbing electrolytes, such as sodium and chloride, but not water. It is impermeable to water, so no significant reabsorption of water occurs here.
b) The descending loop of Henle is permeable to water but not to electrolytes. Water is reabsorbed passively from the tubular fluid, so more water is reabsorbed. However, the concentration and volume of urine do not depend solely on the descending loop of Henle.
c) The distal convoluted tubule and collecting duct are the sites where the concentration and volume of urine mainly depend on water reabsorption. These segments are regulated by hormones like antidiuretic hormone (ADH), which controls the permeability of the collecting duct to water. If ADH is present, more water is reabsorbed, resulting in a concentrated urine volume. If ADH is absent, less water is reabsorbed, leading to a more diluted urine volume.
d) The proximal convoluted tubule reabsorbs the majority of water, electrolytes, and other solutes. However, this segment does not contribute significantly to the concentration and volume of urine.
Based on this information, the correct answer is indeed:
c) distal convoluted tubule and collecting duct.