Endocrinology/VasopressinADH/ControlToWaterIntake/basic

POINT!

With water intake, the (red→blue) negative feedback decreases (the synthesis, secretion, and blood concentration of) vasopressin (anti-diuretic hormone, ADH).

① Water intake decreases plasma osmolarity (becomes diluted, hypotonic), and reabsorption (through the water channels, which are increased by vasopressin, ADH) decreases plasma osmolarity. These effects are in the same direction (red).

② Since these effects are in the same direction (red), negative feedback decreases (blue) (the synthesis, secretion, and blood concentration of) vasopressin (anti-diuretic hormone, ADH). This decreases the number of water channels and the reabsorption of water. The plasma osmolarity-decreasing effect of the reabsorption decreases. This will lead to a reverse in the decreased plasma osmolarity (diluted, hypotonic plasma) produced by water intake, increasing it towards normal (baseline, isotonic) osmolarity.

Challenge Quiz

1.

Water intake increases decreases  正解! plasma osmolarity, and reabsorption (through the water channels, which are increased by vasopressin, ADH) increases decreases  正解! plasma osmolarity. Since these effects are in the same opposite  正解! direction, negative feedback increases decreases  正解! (the synthesis, secretion, and blood concentration of) vasopressin (anti-diuretic hormone, ADH).