The tubular fluid is ____ as it enters Bowman's capsule, ____ at the beginning of the loop of Henle, ____ at the tip of the loop, and ____ as it leaves the loop to enter the distal tubule.
A) isotonic; hypertonic; hypertonic; isotonic
B) isotonic; isotonic; hypotonic; hypotonic
C) isotonic; isotonic; hypertonic; hypotonic
D) hypertonic; hypotonic; hypertonic; isotonic
E) none of these

Question

Quizplus · Accepted Answer

The tubular fluid is isotonic as it enters Bowman's capsule because it has not undergone any reabsorption or secretion yet. It remains isotonic at the beginning of the loop of Henle because both water and solutes are reabsorbed proportionally, maintaining the same concentration. However, as the loop descends, water is reabsorbed from the tubular fluid but solutes are not, resulting in a more concentrated, hypertonic fluid at the tip of the loop. As the fluid leaves the loop to enter the distal tubule, some solutes are actively secreted, but water reabsorption is still occurring passively, resulting in a hypotonic fluid.

The Tubular Fluid Is ____ as It Enters Bowman's Capsule