Anti-Diuretic Hormone (ADH), also known as vasopressin, is crucial for water balance and blood pressure regulation. Produced in the hypothalamus and released by the posterior pituitary, ADH acts on the kidneys to conserve water and control urine volume. It responds to blood osmolarity and volume changes, ensuring fluid homeostasis through a negative feedback mechanism. ADH's action involves increasing the permeability of renal tubules to water by translocating aquaporin-2 channels, thus aiding in water reabsorption and maintaining blood pressure.
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ADH is a peptide hormone produced in the hypothalamus and released by the posterior pituitary gland, which plays a crucial role in regulating water balance in the body
V2 Receptors and Aquaporin-2 Channels
ADH binds to V2 receptors on renal tubule cells, triggering the translocation of aquaporin-2 water channels to increase water reabsorption in the kidneys
ADH secretion is regulated by a negative feedback mechanism, responding to changes in blood osmolarity to maintain fluid homeostasis
An increase in blood osmolarity triggers the release of ADH, promoting water retention and decreasing urine output to restore water potential towards normal levels
A decrease in blood volume or pressure activates baroreceptors, signaling for increased ADH release to maintain optimal levels of both in the body
Dehydration or excessive solute intake can lead to high blood osmolarity, stimulating ADH secretion to prevent water loss
ADH increases the permeability of renal tubule cells to water, promoting its reabsorption back into the bloodstream to maintain fluid balance
ADH can also cause vasoconstriction, helping to elevate blood pressure and maintain optimal blood volume
ADH increases the reabsorption of urea, maintaining a high osmotic gradient in the medullary interstitium to facilitate water reabsorption
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ADH is produced in the ______ and prompts the kidneys to conserve water by acting on the ______ and the collecting duct.
hypothalamus
distal convoluted tubule
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Function of osmoreceptors in hydration monitoring
Osmoreceptors detect blood osmolarity changes, signaling hydration status to hypothalamus.
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Effect of increased blood osmolarity on osmoreceptors
Osmoreceptors shrink, prompting hypothalamus to release ADH, increasing water reabsorption.
