Transport + PCT

Question 1

What types of tubular transport are present in kidneys?

Answer 1

1. Primary active transport
2. Secondary active transport- down concentration gradient

Facilitated Diffusion using:

3. Ion channel- Na/K/Cl
4. Uniporter- conc gradient single substance
5. Paracellular movement- between cells

Question 2

How is water reabsorbed?

Answer 2

No active reabsorbed on, osmotically follows solute reabsorbtion and can be trans cellular or paracellular.

Aquaporins present to enable water reabsorbtion at a rate faster than diffusion.

Question 3

Which aquaporins are involved in renal water reabsorption?

Answer 3

AQ1,2,3

1 - PCT and thin descending limb. Responsible for high permeability to water.

2- collecting tubule- controlled by ADH.

3- collecting tubule- allows water reabsorbed at 2 to exit cells.