Summary

Summary

The cardiovascular system consists of the heart and blood vessels. It provides oxygen and nutrients to tissues while removing wastes. The heart is located within the mediastinum, resting on the diaphragm. It is enclosed in the pericardium, a double-walled sac. The pulmonary circuit consists of vessels that carry blood from the right ventricle to the lungs and back to the left atrium. The systemic circuit consists of vessels that lead from the left ventricle to the body cells and back to the heart, includ-ing the aorta and its branches. The aorta is the largest artery in the body, with respect to diameter.

The wall of the heart has three layers: epicardium, myocardium, and endocardium. The heart is divided into two atria and two ventricles. Blood low in oxygen and high in carbon dioxide enters the right side of the heart and is pumped into the pulmonary circulation. After oxygenation in the lungs and some removal of carbon dioxide, it returns to the left side of the heart. The left ventricle pumps blood out of the heart to the rest of the body.

The cardiac cycle consists of the atria contracting while the ventricles relax, and vice versa. Electrical activity of the cardiac cycle can be recorded via an ECG. The cardiac cycle consists of the P wave, QRS complex, and T wave. Blood vessels form a closed cir-cuit of tubes that carry blood from the heart to the body cells and back again. Blood pressure is the force that blood exerts against the insides of blood vessels. Though the cardiovascular system is usually normal during gestation and childhood, there is the possibil-ity of abnormalities and disorders to develop. Com-mon problems with aging include atherosclerosis, valve thickening, stenosis, and fibrosis. The cardiovas-cular system is seriously damaged by smoking, stress, inactivity, and poor diet.