Controlling blood water potential
Osmoregulation is the control of the water potential of the blood.
Osmoregulation is an example of homeostasis. Changes in blood water potential are detected and corrected so that water balance is maintained.
Specialised sensory neurones called osmoreceptors monitor the water potential of the blood. These receptors are located in the hypothalamus.
Coordination of the response
- Osmoreceptors detect changes in blood water potential.
- The hypothalamus contains the osmoreceptors.
- Nerve impulses influence the posterior pituitary gland.
- The posterior pituitary alters the amount of antidiuretic hormone (ADH) released into the blood.
- ADH travels in the blood to the kidneys and changes water reabsorption.
The response depends on the direction of the change: low blood water potential leads to increased ADH release, whereas high blood water potential leads to reduced ADH release.