What is the function of epithelial cells in relation to capillaries?

Epithelial cells play a crucial role in forming a protective layer, particularly in the context of capillaries. These cells line the surfaces and cavities of various organs and structures in the body, including blood vessels. In capillaries, the epithelial cells create the endothelium, which serves as a barrier between the bloodstream and the surrounding tissues.

This protective layer is significant because it regulates the movement of substances, such as nutrients, waste products, and gases, between the blood and tissues. The selective permeability of the epithelial layer allows for the exchange of materials while helping to protect underlying tissues from potential pathogens and toxins found in the circulating blood. The integrity and health of this epithelial layer are vital for overall vascular function and tissue health.