What type of tissue lines the inner surfaces of blood vessels?

The inner surfaces of blood vessels are lined with endothelial tissue, which is a specialized form of epithelial tissue. Endothelial cells form a thin layer that provides a smooth surface to reduce friction as blood flows through the vessels. This lining is crucial for regulating processes such as the exchange of nutrients and waste products between the bloodstream and surrounding tissues.

Endothelial tissue plays a vital role in the cardiovascular system, including maintaining blood pressure and preventing blood clotting by presenting a non-thrombogenic surface. It also participates in inflammatory responses and the repair of blood vessel injuries.

While other tissue types such as muscle tissue contribute to blood vessel structure (smooth muscle in the middle layer) and connective tissue provides support and elasticity, it is the endothelial tissue specifically that is responsible for lining the inner surface.