Define countercurrent multiplication as it occurs in the kidneys.
A)The exchange of substances in the adjacent limbs of the nephron loop containing fluid moving in opposite directions.
B)The exchange of substances in the adjacent limbs of the nephron loop containing fluid moving in the same directions.
C)The cycling of urea from the collecting duct to the nephron loop and back.
D)The bulk reabsorption of substances in the proximal convoluted tubule and the bulk movement of water due to osmosis.
E)The secretion of ions in response to hormones in the distal convoluted tubule.

Question

Quizplus · Accepted Answer

Countercurrent multiplication refers to the exchange of substances, such as NaCl, between the descending and ascending limbs of the nephron loop. The fluid in the descending limb moves in one direction while the fluid in the ascending limb moves in the opposite direction, creating a countercurrent exchange. This exchange allows for the gradient of NaCl to increase as the fluid moves through the loop, which is necessary for the kidneys to produce concentrated urine.

Define Countercurrent Multiplication as It Occurs in the Kidneys