What causes water reabsorption from the collecting duct? How is this influenced by antidiuretic

What causes water reabsorption from the collecting duct? How...

Key Concepts

Osmotic Gradient

The osmotic gradient in the kidney's medulla is essential for driving water reabsorption by creating a hyperosmolar interstitial environment. This gradient allows water to exit the collecting duct by osmosis when aquaporin channels are present, thereby conserving water in the body.

Aquaporin Channels

Aquaporins are transmembrane proteins that facilitate water transport across cell membranes. In the collecting ducts, ADH promotes the insertion of aquaporin-2 channels into the luminal membrane, enhancing water reabsorption and contributing to the concentration of urine.

Water Reabsorption

Water reabsorption in the kidney is a process where water moves from the collecting duct into the surrounding interstitial space, following an osmotic gradient established by solute accumulation. This mechanism plays a crucial role in maintaining the body's fluid balance and concentrating urine.

Antidiuretic Hormone (ADH)

ADH is a hormone produced in the hypothalamus and released by the posterior pituitary gland that regulates water reabsorption in the kidney. It acts on the collecting duct by binding to receptors on its cells, causing an increase in water permeability through the insertion of specific water channels.

Transcript

0:00 Hello everyone.

00:01 We are going to discuss about the rule of anti -diuratic hormone and reabsorption of water from collecting tubules.

00:19 We all know that antidiarytic is a hormone that decreases the formation of urine.

00:38 Or in other words, we can say that it increases the reabsorption of water.

00:44 It mostly acts on collecting ducts.

00:58 Now we have to discuss that what is the role of idiot that is played on the collecting ducts.

01:07 In order to understand its role we have to see a small diagram of it.

01:12 Suppose we have we have a cell.

01:26 This is a cell of collecting that or principal cell lining the distal tubule or collecting duct.

01:45 And here is a blood vessel flowing in contact with this.

02:01 We label its parts.

02:06 This is the blood vessel and this is lining of the collecting duct, lining cells of cortical collecting duct.

02:34 Now, this is the apical portion of cortical collecting duct cells, while this one towards the blood vessels is bezolateral portion.

02:57 Now, what happens actually? adh molecules flow through bloodstream and reach the cell lining of cortical collecting duct.

03:14 Here we have a g -protein -coupered receptors of seven domains.

03:23 G -protein -couper -receptor.

03:28 It brings about a series of intra -cellar changes inside this cell lining, making the series of reactions very short.

03:41 It happens that here is, okay, we choose red color here.

03:46 Here is the conversion of atp into cyclic ap...

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