What type of pressure is exerted by proteins in blood plasma and interstitial fluid?

The type of pressure exerted by proteins in blood plasma and interstitial fluid is known as oncotic pressure. Oncotic pressure is a form of osmotic pressure that specifically refers to the pull exerted by proteins, particularly albumin, within the blood vessels. These proteins are large molecules that do not easily cross the capillary walls, leading to an imbalance of solute concentrations across the vascular endothelium.

As a result, oncotic pressure helps to retain fluid within the circulatory system and influences the movement of water between blood vessels and surrounding tissues. This is essential for maintaining proper fluid balance and preventing edema. While osmotic pressure in general can refer to the effects of all solutes, oncotic pressure is specifically related to the protein concentration and its effects on fluid distribution in the body, making it the correct answer in this context.