MCQ Detailed View

Anti Diuretic Hormone (ADH), also called vasopressin, is a crucial hormone responsible for regulating the body’s water balance. It is secreted by the pituitary gland, specifically the posterior lobe of the pituitary, which releases ADH under the control of the hypothalamus in the brain.

The primary function of ADH is to reduce water loss from the body. When the body is dehydrated or blood osmolarity increases (meaning blood has a higher concentration of solutes), special receptors in the hypothalamus detect this change. The hypothalamus then signals the posterior pituitary to release ADH into the bloodstream.

Once in circulation, ADH acts mainly on the kidneys, particularly on the collecting ducts of nephrons. It makes the walls of these ducts more permeable to water, allowing more water to be reabsorbed back into the blood instead of being lost as urine. This process helps maintain proper fluid balance, blood pressure, and electrolyte levels in the body.

The other options are incorrect:

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  Pancreas: Secretes insulin and glucagon, which regulate blood sugar levels, not water balance.

  
  


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  Thyroid: Produces hormones like thyroxine (T3, T4) and calcitonin, which regulate metabolism and calcium levels.

  
  


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  None: Incorrect because the secretion source of ADH is well established.

  
  

ADH also plays a role in vasoconstriction (narrowing of blood vessels), which helps raise blood pressure during dehydration or excessive blood loss. A deficiency of ADH can lead to a condition called diabetes insipidus, characterized by excessive urination and thirst.

Therefore, the correct answer is Pituitary gland, as it is the site responsible for releasing Anti Diuretic Hormone that maintains water homeostasis in the human body.