Question

Explain what happens to Na⁺ concentration in the nephron when GFR increases.

Answer 1

When GFR is raised sodium reabsorptionrfrom tubules is increased hence concentration of sodium in tubules is decreased .

Explanation

GLOMERULOTUBULAR BALANCE .

1)An increase in GFR causes an increase in the reabsorption of solutes, and consequently of water, primarily in the proximal tubule, so that in general, the percentage of the solute reabsorbed is held constant

2).This balance between glomerulus and PCT is known as glomerulotubular balance.

3)A cause of glomerulotubular balance is the increased oncotic pressure in the peritubular capillaries

4)When the GFR is high, there is a relatively large increase in the oncotic pressure of the plasma leaving the glomeruli via the efferent arterioles and hence in pertubular capillary  

5)This results in Sodium reabsorption from tubules because increased oncotic pressure in pertubular capillaries try to get the solutes absorbed from tubules and concentration of sodium in tubules is decreased as sodium reabsoprtion is increased .