ANATOMY

Detailed explanation-1: -The primary osmoreceptors that control AVP secretion and thirst are located in the anterior hypothalamus.

Detailed explanation-2: -Osmoreceptors regulate sodium and water balance in a manner that maintains the osmotic pressure of the extracellular fluid (ECF) near an ideal set point.

Detailed explanation-3: -Osmoreceptors in the hypothalamus regulate the amount of ADH released in response to changes in the osmotic pressure of plasma. They are located in the organum vasculosum of the lamina terminalis (OVLT) and the subfornical organ, which are two of the sensory circumventricular organs of the brain.

Detailed explanation-4: -If the water potential of the surrounding extracellular fluid falls (osmolarity or tonicity rises) as a result of water being lost, this is detected by osmoreceptors in the hypothalamus. This then causes the release of ADH into the blood circulation and it passes to the kidneys (as well as the rest of the body).

Detailed explanation-5: -The hypothalamic osmoreceptors then initiate the release of ADH from the posterior pituitary gland. ADH primarily acts on the kidneys to increase the amount of water reabsorbed from the kidney filtrate back into the blood.