What system regulates body water?

Answer 1

I'm assuming you mean "What system controls the water in your body?" This is actually a combination of systems. The Digestive system contains the mouth which takes the water in, and the Large Intestine where most of your water absorption occurs. The water is then moved into the blood stream (part of the Cardiovascular system) and the lymphatic vessels (part of the Lymphatic system) as plasma and lymph (respectively, these are the same fluid, just in diffeent locations, and are a mixture of water and protein). As the Cardiovascular system moves the plasma throughout the body it enters into the kidneys. The kidneys (Part of the Genitourinary system) filter the blood, removing excess water and any waste, converting it into urine. Initially too much water is removed and some of it needs to be reabsorbed. To regulate this the Pituitary gland (part of the Endocrine system, although being located in the brain- which is part of the nervous system) releases a hormone known as Antidiuretic hormone, which will facilitate reabsorption of water in part of the kidneys (not getting into specific anatomy here), bringing it back into the blood stream. Of course you would not have consued the water in the firtp lace unless you felt thirsty. The feeling of thirst comes from the hypothalamus, a structure of the brain that (unlike the pituitary gland) is part of the Nervous system. Take your pick.