4. Osmoregulation

Drinking is also initiated by the osmoreceptors in the hypothalamus. When water potential of blood is lower than normal, osmoreceptors are stimulated, causing a feeling of thirst and thus the person feels the urge to drink water.

When the water potential of blood is higher than normal, osmoreceptors are stimulated. There is no feeling of thirst and thus there is no urge to drink water.