Anatomy and Physiology

Question 1

What is the physiology of ADH and water reabsorption?

Answer 1

1. ADH (also known as vasopressin) is produced by the hypothalamus in response to increased serum osmolality.
2. ADH is transported from the hypothalamus to the posterior pituitary gland.
3. ADH is released into the circulatory system via the posterior pituitary gland.
4. ADH then travels to the kidneys, where it binds to ADH receptors on the distal convoluted tubules.
5. The binding of ADH to these receptors causes aquaporin-2 channels to move from the cytoplasm, into the apical membrane of the tubules:

• These aquaporin-2 channels allow water to be reabsorbed out of the collecting ducts and back into the bloodstream.
• This results in both a decrease in volume and an increase in osmolality (concentration) of the urine excreted.

6. The extra water that has been reabsorbed re-enters the circulatory system, reducing the serum osmolality.
7. This reduction in serum osmolality is detected by the hypothalamus and results in decreased production of ADH.

Question 2

CHECK GEEKY MEDICS FOR MORe?

Answer 2

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