The human body has different systems for handling different functions. All of these systems are vital for health and life. Your heart and arteries are part of the cardiovascular system. The cardiovascular system distributes blood throughout your body. As you explore information about your heart and arteries, you may also hear the term circulatory system. The cardiovascular system is part of your larger circulatory system.

Follow the Blood

Blood travels through your entire cardiovascular system. Blood is actually a tissue that is made up of red blood cells, white blood cells, plasma, platelets and other components. These cells and other substances in blood together serve several critical functions: 

• Delivery of oxygen and nutrients to the rest of the body,
• Removal of carbon dioxide and waste products from the body,
• Infection control, and
• Clotting

To understand the cardiovascular system, we can follow the path of blood, beginning in the heart. The heart is divided into four chambers: the left and right atria and the left and right ventricles. The left ventricle pumps oxygen-rich blood out of the heart and into an artery called the aorta. From the aorta, blood branches out into a series of ever smaller tube-like vessels: arteries, arterioles and finally capillaries. The capillaries deliver the blood's oxygen and nutrients to cells. Then the oxygen-poor blood makes the journey back: from capillaries, to vessels called venules, then to veins, and finally back to the heart.

Before blood can begin its journey around the body again, it must travel to the lungs to release carbon dioxide and take in oxygen. The right atrium accepts the oxygen-poor blood and delivers it to the right ventricle, which pushes the blood through an artery to the lungs. The blood then returns in a vein from the lungs to the left atrium where it waits before passing to the left ventricle and back through the aorta again.

All components of the cardiovascular system are carefully balanced and interdependent. Because of this, when a problem arises in one part of the system, other areas may be affected as well. A person with narrowed coronary arteries, or coronary artery disease, is likely to have narrowed arteries in the legs as well. (This is known as peripheral artery disease, or PAD.) Similarly, a person with narrowing in the arteries leading to the kidneys (called kidney artery disease or renal artery disease) may also have narrowing in the main artery leading to the brain.

This is why diseases of the cardiovascular system put people at risk for a number of conditions, such as heart attack, stroke, kidney failure and other serious illnesses.