Your Heart
When working correctly, the heart pumps an average of 6 liters of blood every minute of your life through its four chambers:
- Two upper chambers, the atria, move blood returned from your body and lungs to the more muscular lower chambers.
- Two lower chambers, the ventricles, pump the blood back to the lungs and body.
- The right side of the heart is responsible for taking blood returning from the body and pumping it to the lungs where it is freshly oxygenated and waste gases are removed.
- The left side of the heart is responsible for taking freshly oxygenated blood from the lungs and pumping it to every cell in your body.
Your Heart's Circulatory Systems
Like all muscles, the heart requires a constant supply of fresh blood, carried through two main arteries (left and right main coronary arteries), which branch into major circulation systems that supply the left and right side of the heart.
The left main coronary has two major systems, the Left Anterior Descending (LAD) coronary artery and the Circumflex (Cx) coronary artery. The LAD services about 40% of the heart muscle. Since it services the left ventricle, is the most important. It normally has at least one diagonal branch, plus numerous others that serve the septum, the wall between the left and right side of the heart. The circumflex system serves the left lateral, or side, wall and the back, or posterior, of the left side of the heart, giving rise to several Obtuse Marginal (OM) branches that span out over its territory.
The right main coronary artery has several branches. The Acute Marginal (AM) branch provides flow to the front of the right side of the heart. As it proceeds toward the apex of the heart, it splits into the Posterior Descending (PD) and Posterior Lateral (PL) branches, which provide the major circulation to the right ventricle and septum. Blood is returned to the right atrium via a series of coronary veins that come together in the coronary sinus.
Blockages in these arteries cause the heart muscle to become oxygen-poor, or ischemic. Ischemic heart muscle cannot contract efficiently, which is known as heart failure. The heart has pain sensors which serve to warn when it is ischemic. This pain is called angina and is a serious indication that something is wrong with the heart (though some people with this problem have no pain).
Heart Valves
The heart has four valves, which ensure blood flows in only one direction.
- The tricuspid valve has three leaflets and lies between the right atrium and right ventricle. It's job is to keep blood from backing up into the atrium.
- The pulmonic valve also has three leaflets and ensures that blood pumped by the right ventricle proceeds in a forward direction through the lungs. For adults, surgery on the pulmonic valve is rare.
- The mitral valve has two leaflets and is responsible for ensuring that blood returned from the lungs flows in one direction into the left ventricle.
- The aortic valve is normally a tri-leaflet valve that sits at the exit from the left ventricle where aorta meets the heart. It is responsible for ensuring that blood leaving the heart heads downstream to the body.
Problems with the heart valves disrupt the circulation and can lead to life-threatening conditions. Fortunately, the damage occurs slowly and can usually be managed medically in the early stages. Some valve problems are congenital (you were born with them) while others have other causes. Some of these valve problems can be repaired while others must be replaced.
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1-877-233-WELL (9355).