Session 4 - Notes

Question 1

What is the major cation lost in sweat?

Answer 1

Sodium

Question 2

How much water is lost in each part of the nephron?

Answer 2

H20
PCT - 65%
Loop of henle 
Descending - 10%
Ascending - 0%
DCT - 10%
CD - 5%

Question 3

What are the three major driving forces which move Na+ from tubular cells into the peritubular capillaries?

Answer 3

Hydrostatic pressure in the intracellular space
Higher oncotic pressure in peritubular capillaries
Lower hydrostatic pressure in peritubular cappilaries

Question 4

What histological features of the epithelial cells lining the descending limb of the
loop of Henle indicate that they are not involved in active transport?

Answer 4

Squamous epithelium, no brush border, no mitochondria

Question 5

Why does the process of glomerular filtration facilitate the reabsorption of solute
and solvent from the inter-cellular spaces?

Answer 5

~20% of solute and water filtered in glomerulus enters kidney tubule. This leaves
protein behind in peritubular capillaries thus higher oncotic pressure; this then
draws water and solute into the blood in these capillaries.