If a person drinks a lot of water, the water content of their blood will increase. Describe how the water content of their blood is regulated.

Osmoreceptors in the hypothalamus detect the increase in water concentration. This stimulates the pituitary gland to release less ADH. This reduces the amount of ADH in the blood and so, reduces the amount of ADH reaching the collecting ducts in the Kidney. The decrease in ADH causes a decrease in the permeability of the collecting ducts causing less water to be reabsorbed. This means that the urine will become more diluted, returning the water content in the blood back to a normal level.