The healthy heart
About the heart:
The heart is the hardest working muscle in the human body. Located almost in the center of the chest, the adult human heart is about the size of two fists.
At an average rate of 80 times per minute, the heart beats about 115,000 times in one day or 42 million times in a year. During an average lifetime, the human heart will beat more than 3 billion times - pumping an amount of blood that equals about 1 million barrels, enough to fill more than 3 super tankers. Even at rest, the heart is continuously working.
The cardiovascular system, composed of the heart and blood vessels, is responsible for circulating blood to supply the body with oxygen and nutrients. This system works by:
- Pumping blood through the lungs to remove carbon dioxide and to refresh the blood with oxygen
- Pumping oxygenated blood to provide the body with oxygen and nutrients and to remove waste products
- Supplying blood and oxygen to the heart muscle via the coronary arteries.
How the heart works
The heart is the muscle that pumps blood filled with oxygen and nutrients through the blood vessels to the body tissues. It is made up of:
- Four chambers (two atria and two ventricles) that receive blood from the body and pump out blood to it.
- The atria receive blood coming back to the heart.
- The ventricles pump the blood out of the heart. - Blood vessels, composed of a network of arteries and veins, that carry blood throughout the body.
- Arteries transport blood from the heart to the body tissues.
- Veins carry blood back to the heart. - Four valves to prevent backward flow of blood.
- Each valve is designed to allow the forward flow of blood and prevent the backward flow. - An electrical system of the heart that stimulates contraction of the heart muscle.
What are the different coronary arteries?
The two main coronary arteries are the left and right coronary arteries. The left coronary artery (LCA), divided into the left anterior descending artery (LAD) and the circumflex branch (Cx), supplies blood to the left ventricle and left atrium. The right coronary artery (RCA), divided into the right posterior descending and acute marginal arteries, supplies blood to the right ventricle, right atrium, and sinoatrial (SA) or Sinus Node (cluster of cells in the right atrial wall that regulates the heart's rhythmic rate).
Since coronary arteries deliver blood to the heart muscle, any coronary artery disorder or disease can have serious implications by reducing the flow of oxygen and nutrients to the heart, which may lead to a heart attack and possibly death. Atherosclerosis (a build-up of plaque in the inner lining of an artery causing it to narrow or become blocked) is the most common type of heart disease.
