Why proteins not pass out through the blood?

Proteins are too large to pass out through the blood because they cannot fit through the pores in the blood vessels. The pores in blood vessels are very small, and they can only allow small molecules, such as water, oxygen, and glucose, to pass through. Proteins are much larger than these molecules, so they cannot fit through the pores.

This is important because it means that proteins cannot leak out of the blood vessels and into the surrounding tissues. If proteins did leak out of the blood vessels, it would cause a lot of problems, such as swelling and inflammation.

The fact that proteins cannot pass out through the blood is also important for drug delivery. If a drug is too large to fit through the pores in blood vessels, it cannot be given intravenously. This means that drugs that are too large must be given in a different way, such as by injection into the muscle or by oral administration.