Do substances in the kidney move from the glomerulus to Bowman's capsule by reabsorption?

1 Answer
Nov 16, 2017

No, not by reabsorption,
By Utrafiltration.


Ultrafiltration in nephron:
Glomerulus is like a ball of capillaries and Bowma's capsule is a cup-shaped structure hugging the glomerulus. Now there are following steps that occur during Ultrafiltration:

  • Blood enters the glomerulus through afferent arterioles.
  • As glomerulus has a continuous wrapping of arterioles. So, the question arises that how filtrate get its way to the bowman's capsule?
  • The answer is that the endothelial cells' layer of the glomerulus' arterioles are fenestriated or porus(having holes).
  • Thus these holes can allow certain components of blood i.e ions, proteins, glucose molecules and blood cells to pass through them.
  • But there is another layer next to it which is known as basement membrane. This semi-permeable membrane hinders the passage of larger molecules. It basically helps to make sure that only small substances pass through. And the larger proteins or other largermolecules bounce back through the basement membrane.
  • So, that the glomerular filtrate containing smaller components i.e ions, amino acids and glucose gets its way to Bowman's space by passing through the Podocytes or epithelial cells which lie next to basement membrane.
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The substances when enter the glomerulus they are filtered into bowman's capsule. So there is no reabsorption. However, reabsorption occurs next to ultrafiltration.

Hope it helps...