Anti Diuretic Hormone (ADH) – Class 11 | Chapter – 22 | Biology Short Notes Series PDF

Anti Diuretic Hormone: ADH, also known as arginine vasopressin, is a hormone produced by the hypothalamus and stored in the posterior pituitary gland. It is made up of special nerve cells found at the base of the hypothalamus. The hormone is transported to the pituitary gland via axons, where it is released into the bloodstream. It regulates and balances the amount of water in the blood.

Functions Of Anti Diuretic Hormone

  • It acts on the kidneys and the blood vessels and functions to control the blood pressure. Higher concentrations of ADH constrict the blood vessels which increases the blood pressure.
  • It allows the water in the urine to be taken back in a specific area in the kidney and thus reduces the amount of water excreted through the urine thereby conserving the volume of the fluid in the body.
  • It is mainly responsible for homeostasis.

Regulation Of Anti Diuretic Hormone

The release of Anti Diuretic Hormone into the bloodstream is regulated by a number of factors:

  • The decrease in the blood volume or blood pressure is detected by the large blood vessels and the receptors present in the heart, which stimulate the release of ADH.
  • The increase in the concentration of salts in the bloodstream also controls the secretion of ADH which is identified by special nerve cells in the hypothalamus.
  • Alcohol prevents the release of ADH. This causes dehydration and an increase in urine production.

If the levels of ADH are higher, the water is retained by the kidney in the body. If excess ADH is released when not required, the blood gets diluted due to excess water retention. The salt concentration in the blood thus decreases. High levels of ADH may be caused due to the side-effects of drugs, lung diseases, etc. Increased ADH is associated with leukaemia, lymphoma, bladder cancer, brain cancer, etc.

If the levels of ADH are lower, a lot of water is excreted by the kidneys. This increases urine volume and lowers blood pressure. Low levels of ADH indicate primary polydipsia and damage to the hypothalamus or pituitary gland. Diabetes insipidus is related to low levels of ADH.

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By Team Learning Mantras