The pulmonary circuit moves blood from the right side of the heart to the lungs and back to the heart. Although arteries and veins differ structurally and functionally, they share certain features.įigure 1. Pulmonary veins then return freshly oxygenated blood from the lungs to the heart to be pumped back out into systemic circulation. In contrast, in the pulmonary circuit, arteries carry blood low in oxygen exclusively to the lungs for gas exchange. The blood returned to the heart through systemic veins has less oxygen, since much of the oxygen carried by the arteries has been delivered to the cells. Systemic arteries provide blood rich in oxygen to the body’s tissues. Eventually, the smallest arteries, vessels called arterioles, further branch into tiny capillaries, where nutrients and wastes are exchanged, and then combine with other vessels that exit capillaries to form venules, small blood vessels that carry blood to a vein, a larger blood vessel that returns blood to the heart.Īrteries and veins transport blood in two distinct circuits: the systemic circuit and the pulmonary circuit. An artery is a blood vessel that carries blood away from the heart, where it branches into ever-smaller vessels. Explain the structure and function of venous valves in the large veins of the extremitiesīlood is carried through the body via blood vessels.Describe the basic structure of a capillary bed, from the supplying metarteriole to the venule into which it drains.
Distinguish between elastic arteries, muscular arteries, and arterioles on the basis of structure, location, and function.Compare and contrast the three tunics that make up the walls of most blood vessels.By the end of this section, you will be able to:
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