What layer of the arterial wall is made up of fibrous connective tissue?

The layer of the arterial wall that is made up of fibrous connective tissue is known as the tunica externa. This layer, also referred to as the adventitia, serves several critical functions in arterial structure. It provides structural support and protection to the vessel, anchoring it to nearby tissues and organs. The fibrous connective tissue within the tunica externa is composed primarily of collagen and elastin fibers, which impart strength and elasticity to the artery, helping it withstand various pressures and stresses during blood flow.

In addition to its supportive role, the tunica externa also contains smaller blood vessels, known as vasa vasorum, that supply blood to the tissue of the arterial walls, especially in larger arteries. Understanding the distinct functions of this layer is vital for grasping the overall anatomy and physiology of blood vessels, as well as the pathological changes that can occur in vascular diseases.

The other layers of the arterial wall—tunica intima, tunica media, and the redundancy of naming tunica externa as adventitia—serve different structural and functional purposes. The tunica intima is the innermost layer and consists of endothelial cells, while the tunica media is the middle layer composed primarily of smooth muscle and elastic fibers, which regulate the diameter