what is the structure and function of arteries, veins and capillary?
Arteries have three layers: the inner layer lined by endothelium, a thick layer of muscle and elastic fibres and the connective tissue layer. Arteries carry blood away from the heart to the body organs.
Veins consist of three layers: the outer layer of connective tissue, a middle layer of smooth muscle and the inner layer lined with endothelial cells. Veins are vessels that support circulation by transporting blood to the heart.
Capillaries are composed of only two layers of cells - an inner layer of endothelial cells and an outer layer of epithelial cells. The primary function of capillaries is the exchange of substances between the blood and tissues.