Originally posted by Lucy Loo
Antidiuretic hormone (ADH)- a hormone secreted in mammals by the pituitary gland
Awww... *horror horror horror* Antidiuretic Hormone is NOT made in the pituitary gland, repeat, it's NOT made in the pituitary gland. It is made in the hypothalamus and stored in the prosterior pituitary gland and is used to stimulate water reabsorption. This is achieved by the ability of the hormone to make the distal convoluted tube (after the loop of Henle) become more permeable to water, thus, increases its abilith to absorb water.
Despite the body's actually need of water, the salt concentration is the primary determinant to the retention or release of water. By increasing the concentration of water, the concentration of the salt will be reduced. (Note: no salt is lost, only the concentration is altered). However, the body has to maintain the volume of water in the body as well as the concentration of salt. If the amount of water has reached its optimum, the concentration of salt cannot be simply maintained by the flow of water and this is where your aldosterone comes in.
Aldosterone is produced in the adrenal cortex and it reduces the reabsoroption of K+ ions and increaces the reabsorption of Na+ ions. (The balance of K+ ions and Na+ ions is essential to the function of the nervous system.. hehee.. this is how pesticides work, they stuff up *colloquialism comes in* the nervous system of whatever you are spraying, there are a few ways to do it... aww.. better go back to aldosterone...) Hmm.. if you do Chemistry then this helps a lot.. anyways, Na+ ions in the plasma is usually a result of dissolved NaCl in your body, therefore the reabsorption of Na+ will also triggers the reabsoption of Cl- ions (if no Cl- ions are absorbed.. you will have negatively charged pee...) The reasorption on these ions will increase the concentraion, thus, will lead to the reabsorption of water to balance the increase in salt concentration. The water will then be balanced by ADH again.