Question

Describe the structure of an artery and a vein. Explain how their structure helps in their functioning.

Answer 1

Arteries are the blood vessels made up of three layers which convey blood from the heart to the tissues of the body. The outer layer is made up of connective tissues and contain elastic and collagen fibres, which provides the support to the blood vessel. The middle layer made up of smooth muscles, collagen and a large amount of elastic fibres. This layer provides the strength and elasticity. Elastic fibres allow the wall to stretch. The inner endothelium is composed of very smooth epithelial cells, which helps in, minimizing the friction. Veins are similar to arteries in structure except for these three layers which are thin and elastic. In veins, the muscle sand connective tissues in veins are poorly developed. The collagen fibres of the outer layer are well developed. The middle layer in most of the veins is very thin with no muscles. Semilunar valves are found in the lumen of some veins to allow the flow of blood in only one direction i.e., towards the heart.