The ____ establish the medullary vertical osmotic gradient by means of countercurrent multiplication.
A) loops of Henle of juxtamedullary nephrons
B) loops of Henle of cortical nephrons
C) vasa recta of juxtamedullary nephrons
D) vasa recta of cortical nephrons
E) vasopressin-secreting cells

Question

Quizplus · Accepted Answer

The loops of Henle of juxtamedullary nephrons establish the medullary vertical osmotic gradient by means of countercurrent multiplication. This gradient is important for water reabsorption and concentration of urine. The loops of Henle of cortical nephrons do not extend far enough into the medulla to contribute significantly to the vertical gradient. The vasa recta of both types of nephrons help to maintain the gradient but do not establish it. Vasopressin-secreting cells (in the hypothalamus and posterior pituitary) respond to changes in osmolality and regulate water reabsorption in the collecting ducts, but they do not establish the medullary osmotic gradient.

The ____ Establish the Medullary Vertical Osmotic Gradient by Means