Which of the following pairs correctly completes the sentence about nephron blood flow: "Hydrostatic pressure pushes blood to nephron; _______ pressure pulls blood to capillary"?

The correct answer is osmotic pressure. In the context of nephron blood flow, hydrostatic pressure refers to the pressure exerted by the fluid (blood) within the capillaries, which forces fluid out into the renal tubule. This process is essential for filtration in the kidneys, allowing water and smaller solutes to pass into the tubule while retaining larger molecules like proteins in the bloodstream.

Osmotic pressure, on the other hand, is primarily due to the presence of solutes in the blood, such as proteins (like albumin) that are too large to pass through the capillary walls. This pressure creates a gradient that draws water back into the capillaries, effectively pulling blood toward them. The balance between hydrostatic pressure pushing blood out and osmotic pressure pulling fluid back into the capillaries is crucial for maintaining homeostasis and proper kidney function.

Other pressures mentioned, such as hydraulic, arterial, and atmospheric, do not play a direct role in the mechanisms of fluid movement into or out of the nephron surrounding blood flow. Hydraulic pressure is not a commonly recognized term in this context, arterial pressure specifically refers to blood pressure within arteries rather than the forces acting on nephron filtration, and atmospheric pressure is unrelated to the