Circulatory_System

Circulatory System Blood must be moved through the body continuously throughout an animal’s life. Every human’s heart consists of muscular chambers capable of strong contractions. Chambers called atria collect blood. Atrial contractions send blood into the ventricles, which are chambers whose contractions circulate blood through the body. Arteries and arterioles are thick-walled vessels that carry blood away from the heart. Arteries carry blood away from the heart. These vessels have thick walls embedded with smooth muscle and elastic tissue. With each surge of blood from the ventricles, the arteries expand slightly. As their elastic walls recoil between heartbeats, the arteries actually help pump the blood and maintain a steady flow through the smaller vessels. Arteries branch into vessels of smaller diameter called arterioles, which play a major role in determining how blood is distributed within the body. Human hearts can be considered as two separate pumps, each with two chambers. In each pump an atrium receives and briefly stores the blood, passing it to a ventricle that propels it through the body. One pump, consisting of the right atrium and right ventricle, deals with deoxygenated blood. The right atrium receives oxygen-depleted blood, heart, through, body, veins, never, ventricle, right, now, chambers, atrium, vessels, know, knew, contractions, called, arteries, ventricles, learned, cells, after, red, pump, left, class, carry, before, away, walls, term, something, really, pulmonary, oxygen-depleted, muscular