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Osmoregulation

Explain how osmoregulation is used to regulate water levels in the body, looking at hormones and the kidneys as well as water levels within cells
Original post by hattie021098
Explain how osmoregulation is used to regulate water levels in the body, looking at hormones and the kidneys as well as water levels within cells


Osmoregulation is the homeostatic regulation of osmotic pressure in the body in order to maintain constant water content, so it prevents fluid in body from becoming too concentrated/dilute.

The kidneys are involved in excretion of waste such as urea, which leaves the body via urine. If there's lots of water in the body, osmoreceptors in the hypothalamus detect this and signal to the pituitary gland to secrete less of the hormone ADH (anti-diuretic hormone). ADH targets endothelial cells in the collecting ducts, which are present in the nephrons within the kidney. This reduces the permeability of the collecting duct and distal convoluted tubule walls, so less water is reabsorbed by osmosis, and urine is high in volume, and dilute - so pale in colour.
If you are dehydrated, the osmoreceptors in hypothalamus detect this and send signals to the pituitary gland to secrete more ADH increasing permeability of the collecting duct walls/distal convoluted tubule walls. This means more water can be reabsorbed by osmosis to use in the body, and urine is lower in volume, and concentrated, meaning it is dark yellow in colour. This occurs in the kidney as they help control water loss (via urine and sweat).

This is a negative feedback system, which allows the body to remain in a isotonic solution so metabolic processes can occur (level of salts and ions etc to be able to dissolve in blood), maintaining constant osmotic pressure.

In the kidney, the Loop of Henle helps produce a low water potential in the medulla. The descending limb allows water to move out by osmosis (is permeable) decreasing the water potential of the filtrate. The ascending limb of the Loop of Henle is impermeable to water molecules and only allows chloride ions and sodium ions to move out by active transport so the water potential of filtrate rises. This a counter current multiplier mechanism as it produces the concentration gradients. At the bottom of the loop the concentration is isotonic.

Not sure how much detail you wanted to go into but ADH works by activating enzymes when it binds to plasm membrane - hope this helps!! x
Original post by thaliajade08
Osmoregulation is the homeostatic regulation of osmotic pressure in the body in order to maintain constant water content, so it prevents fluid in body from becoming too concentrated/dilute.

The kidneys are involved in excretion of waste such as urea, which leaves the body via urine. If there's lots of water in the body, osmoreceptors in the hypothalamus detect this and signal to the pituitary gland to secrete less of the hormone ADH (anti-diuretic hormone). ADH targets endothelial cells in the collecting ducts, which are present in the nephrons within the kidney. This reduces the permeability of the collecting duct and distal convoluted tubule walls, so less water is reabsorbed by osmosis, and urine is high in volume, and dilute - so pale in colour.
If you are dehydrated, the osmoreceptors in hypothalamus detect this and send signals to the pituitary gland to secrete more ADH increasing permeability of the collecting duct walls/distal convoluted tubule walls. This means more water can be reabsorbed by osmosis to use in the body, and urine is lower in volume, and concentrated, meaning it is dark yellow in colour. This occurs in the kidney as they help control water loss (via urine and sweat).

This is a negative feedback system, which allows the body to remain in a isotonic solution so metabolic processes can occur (level of salts and ions etc to be able to dissolve in blood), maintaining constant osmotic pressure.

In the kidney, the Loop of Henle helps produce a low water potential in the medulla. The descending limb allows water to move out by osmosis (is permeable) decreasing the water potential of the filtrate. The ascending limb of the Loop of Henle is impermeable to water molecules and only allows chloride ions and sodium ions to move out by active transport so the water potential of filtrate rises. This a counter current multiplier mechanism as it produces the concentration gradients. At the bottom of the loop the concentration is isotonic.

Not sure how much detail you wanted to go into but ADH works by activating enzymes when it binds to plasm membrane - hope this helps!! x

thats amazing thank you so much!!

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