About counter current mechanism

In summary, the medulla's hyperosmotic nature causes water to flow out of the collecting tubules and concentrate the urine. However, the vasa recta, which are also in the hyperosmotic medulla, are able to absorb water due to the dominant osmotic pressure in the peritubular capillaries. This process helps to maintain the concentration of the urine and regulate water balance in the body.
  • #1
keep@science
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As medulla is hyperosmotic with respect to medullary collecting tubules (I.e. main site for water absorption )water flows out of the collecting tubules and urine get concentrated ...But how it enters vasa
recta since vasa recta is also going through same hyperosmotic medulla ,how it absorbs The water ?
 
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  • #2
This isn't my area of expertise, so take this with a grain of salt, but...

It's not just osmotic pressure that forces water out of the glomerulus and into the Bowman's capsule. It's also hydrostatic pressure (basically, plain old blood pressure). So the total (osmotic + hydrostatic) pressure gradient in the renal corpuscle pushes water and small molecules out of the bloodstream and into the urinary ultrafiltrate.

However, once the filtered blood passes out of the glomerulus, the hydrostatic pressure in the bloodstream drops and the osmotic pressure between the peritubular capillaries and the collecting tubules dominates the net direction of water flow. Since the blood in the peritubular capillaries is hyperosmotic compared with the collecting tubules, water flows back into the bloodstream, concentrating the urine.
 
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What is the counter current mechanism?

The counter current mechanism is a biological process that involves the flow of fluids in opposite directions. This mechanism is commonly observed in the kidneys, where it helps to maintain the concentration gradient necessary for filtering and reabsorbing essential substances from the blood.

How does the counter current mechanism work?

In the kidneys, the counter current mechanism involves the flow of blood and urine in opposite directions through long, hair-like structures called nephrons. This allows for the exchange of substances, such as sodium and water, between the blood and urine, maintaining a concentration gradient that is necessary for proper kidney function.

What is the role of the counter current mechanism in the kidneys?

The counter current mechanism plays a crucial role in maintaining the concentration gradient necessary for the kidneys to filter waste products from the blood and reabsorb essential substances. It also helps to conserve water and maintain electrolyte balance in the body.

What are the advantages of the counter current mechanism?

The counter current mechanism has several advantages, including the efficient exchange of substances between fluids, the conservation of water, and the ability to maintain a concentration gradient necessary for proper kidney function. It also allows for the removal of waste products and helps to regulate blood pressure.

Can the counter current mechanism be found in other biological systems?

Yes, the counter current mechanism is not limited to the kidneys and can also be found in other biological systems, such as the respiratory system, where it helps to maintain the concentration gradient necessary for gas exchange in the lungs.

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