Zoology - Body Fluids and Circulation Question with Solution | TestHub

Capillaries are the smallest blood vessels in the body. Capillary has no muscular wall. Its, wall is made of a single layer of flat endothelial cells and is consequently very permeable-to water and small- solutes, but not to proteins and other macromolecules. The diameter of lumen of capillaries is from 7.5 µm to 75 µm. Only about 5 to 7% of the total volume of blood is contained in the capillaries.