List the features of blood vessels.

Blood vessels are part of the circulatory system and are used to transport blood throughout the body. The most important types – arteries and veins – carry blood from the heart or to the heart, respectively.

All blood vessels have the same basic structure. The inner lining is the endothelium and is surrounded by subendothelial connective tissue. Around it there is a layer of vascular smooth muscle, which is well developed in the arteries. Finally, there is another layer of connective tissue known as adventitia, which contains the nerves that supply the muscle layer as well as the nourishing capillaries in the large blood vessels.