Water balance in the body is extremely important. We can’t have too much water in our bodies and without water, our cells couldn’t function properly. Our body tries to keep a balance of the water coming into the body (through food and drinks), and the water leaving the body (through sweating, faeces and urine).

So how does the body control our water levels?

Step 1

Receptors in the hypothalamus detect a that there is a drop in the level of water in the blood.

The hypothalamus sends a message to the pituitary gland telling it to release ADH (Anti-Diuretic Hormone)/ Vasopressin

Its a hot day and your on a run

You start to sweat and haven’t drunk in a while

The pituitary gland receives a message from the hypothalamus and releases ADH.

ADH travels through the blood to the kidneys having an effect on the kidneys and blood vessels throughout the body.

ADH tells your kidneys to absorb more water from drinks and food. Releasing the water into the blood stream. This occurs in the loop of henle.

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This in turn makes you urinate less.

Step 2

Step 3

ADH also has an effect on the blood vessels through out the body. They cause them to constrict, increasing blood pressure.

Step 4

Receptors in the hypothalamus detect a a rise in water levels and stops the signal to produce ADH in the pituitary gland.

Reaching homeostasis.

Bellow is an animation of the feedback system

Click here for a test on hormones and the endocrine system