ADH & Osmoregulation

Osmolarity

Osmolarity

measurement of how concentrated solutes are in a solution. higher solute concentration = higher osmolarity

What is osmolarity controlled by?

the hypothalamus through the pituitary gland

What does the pituitary gland do?

releases hormone ADH into bloodstream

How does ADH work?

binds to receptors in collecting duct - makes membrane more permeable to water. water flows OUT of collecting duct to peritubular capillaries - darker urine.

When will ADH be released?

when the osmolarity in our bodies is high

1

Hypothalamus

2

Pituitary gland (releases ADH)

3

thirst

4

drinking water to relieve thirst

5

osmolarity returns to set point

6

ADH

7

Collecting duct

8

water

9

Peritubular capillaries

10

high water concentration in blood - osmolarity decrease

How does ADH make the collecting duct's membrane more permeable to water?

inserts aquaporins (protein channels) onto membrane