Question 32

[yvettew_ol7596]

Isn't the driving force for the initial filtration step due to hydrostatic pressure? Hydrostatic pressure is due to the concentration of the plasma compared to the concentration on the other side of the tubular membrane, in so that it will pull the plasma out of the vessels and into the tubular membrane. I don't see how hydrostatic pressure has any relation with blood pressure because even if your blood pressure is high, but your plasma is at the correct right concentration, your plasma will not be filtrated. Therefore, I do not agree with B being the best choice. I would think C. "chemiosmotic gradient across the semipermeable tubular membrane", a better answer.

Can someone please clarify this distinction for me? Thanks.

[jellywing_2058]

There seems to be a confusion between the different types of pressure.

Osmotic pressure: Pressure due to the concentration of plasma.

Hydrostatic pressure: Blood pressure. It is the pressure a fluid has on the walls of a closed system.

In the nephron, the capillaries of the glomerulus are between an arteriole and a vein. The blood pressure is higher than the osmotic pressure, therefore fluid moves out of the glomerulus blood vessels into the capsule, where the filtrate accumulates.

[admin]

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