When you were about four weeks old in the womb, your heart began to form. Your heart will beat nearly three billion times in your lifetime.
Your heart is a hollow muscle about the size of your closed fist. Every time your heart ‘beats’, it pumps blood containing oxygen and nutrients to all parts of your body. Blood is carried to your tissues and organs through a network of blood vessels called arteries. A single red blood cell makes approximately 250,000 round trips of the body before returning to the bone marrow, where it was born, to die.
Sometimes this wonderful organ can develop problems. This section attempts a brief description of the heart and common cardiac problems.
The Anatomy - simplified
Your heart is made up of four chambers. There are two chambers on top and two below.
The upper chambers are called atria. (Each upper chamber is called an atrium). The lower chambers are called ventricles. There are muscle walls called septa separating the left and the right atrium, and the left and right ventricles. Blood flows from the atrium to the ventricle through valves. Valves work like one-way doors, letting blood flow through them in only one direction.
Within the heart the blood flows thus:
The impure blood from the rest of the body is brought to the right atrium. Then it passes into the right ventricle. The right ventricle contracts and blood is forced into the pulmonary artery. This blood travels through the lungs. The blood is purified or oxygenated in the lungs and this returns to the heart at the left atrium. Then the blood falls into the left ventricle. The ventricle contracts and the blood goes rushing into the aorta and to the other parts of the body.
The Circulatory System
Your heart pumps blood to all parts of your body through the “systemic circuit”. Pure blood from the heart, carried through the aorta, goes to all the organs of the body through the arteries and the impure blood is gathered by the veins and returned to the heart.
The heart sends the impure blood collected thus to the lungs through the pulmonary artery to be purified by the lungs. It collects the pure blood through the pulmonary vein. This routing of blood to the lungs and back forms the “pulmonary circuit”.
To do both these functions(pumping blood to the rest of the body and sending blood to be purified in the lungs) effectively, the heart needs a supply of oxygenated blood, just like any other part of the body. The coronary arteries that rise from the aorta supply oxygen rich blood to the heart muscle.
Two main coronary arteries feed the heart. The right coronary artery feeds the right side and bottom part of the heart. The left main coronary artery has two branches; the left anterior descending artery, which feed the front left side of the heart, and the circumflex artery which feeds the back of the heart. These main coronary arteries have many branches, which supply the heart muscle with oxygen-rich blood.
Defects/ diseases of the heart
Heart problems can be classified into two broad categories: