Anatomy, Blood Flow

Excerpt

Blood flow through the body delivers oxygen, nutrients, hormones, cells, products of defense mechanisms for wound healing, and platelets. The heart pumps these products to the organs, while the vessels transport them to and from the organs. Arteries perfuse the organs and veins drain the organs of waste products. The lymphatic system helps in draining excess tissue fluid to the bloodstream. Two circulatory loops are most important to survival: the pulmonary circulation and the systemic circulation. The pulmonary circulation pumps blood from the right ventricle to the pulmonary artery. Blood exchanges carbon dioxide for oxygen while passing through the lung and the newly oxygenated blood drains into the left atrium from the pulmonary veins. The other circulatory loop is the systemic circulation, which pumps blood from the left ventricle to the aorta to the rest of the body. It transports nutrients to the intestines and hormones to endocrine glands. Waste excretion then occurs via the kidneys, intestines, lungs, and skin. Blood returns to the right atrium from the superior and inferior vena cava.