Question

What causes fluid and solutes to move out of the blood and through the filtration membrane is:

A. they are moved by secondary active transport

B. they are attracted towards the capsular space by the oncotic pressure of the filtrate

C. they are forced out by the blood oncotic pressure

D. they are pushed by the glomerular hydrostatic pressure

E. solutes move by facilitated diffusion; water moves by osmosis

Answer 1

The answer is B

Glomerular filtration is a passive process and energy is not used in filtration by the filtration membrane to produce filtrate.

GFR is influenced by multiple factors and forces.

• The blood inside the glomerulus creates glomerular hydrostatic pressure.This causes the movement of fluid out of the glomerulus into the glomerular capsule.
• The capsular hydrostatic pressure opposses the glomerular hydrostatic pressure. This causes movement from the capsule to the capillary.
• The concentration of the solutes in the fluids affects net movement.
• The blood oncotic pressure draws fluid back to the blood vessel.