The right ventricle is composed of three layers. The endocardium which is the inner surface of the endothelim supported by connective tissue fibers. The myocardium or cardiac muscle which is reposnible for the pumping action of the heart. Lastly, the epicardium which is an outer surface of mesothilial cells supported by dense irregular connective tissue.

The elastic arteres are large vessels that convey blood from the heart to systemic and pulmonary circulations. During systole, the high pressure causes the wall to distend, the walls then deflate during the relaxation phase of the cardiac cycle enabling the blood to move through the arteries.

Large vein or the brachiocephalic veins have thinner walls than arteries with less distinct layers. These veins are large venous structures located within the thorax, originating from the union of the subclavian vein witht he internal jugular vein. It drains blood from the head and neck, upper limbs and the upper part of the thorax.