# Action against heart diseases
## Introduction to Heart Disease

The heart is like any other muscle, requiring oxygen and nutrient-rich blood for it to function. The coronary arteries that supply blood to the heart muscle spread across the surface of the heart, beginning at the base of the aorta and branching out to all areas of the heart muscle.
The coronary arteries are at risk for narrowing as cholesterol deposits, called plaques, build up inside the artery. If the arteries narrow enough, blood supply to the heart muscle may be compromised (slowed down), and this slowing of blood flow to the heart causes pain, or angina.
A heart attack or myocardial infarction occurs when a plaque ruptures, allowing a blood clot to form. This completely obstructs the artery, stopping all blood flow to part of the heart muscle, and that portion of muscle dies.
The great throbbing center of all human life and activity is the heart. No other organ carries so much responsibility for the rest of the body. Every part of the human system is entirely dependent upon the heart. The lungs enable us to breathe. The kidneys filter out the waste material from the blood. But the one great organ upon which all the others depend is the heart. Constantly, day and night,your wonderful heart continues to beat. When you are at rest, it beats quietly and slowly, conserving its great reserve powers for the time when they might be sorely needed. If an emergency should arise, your heart will immediately quicken its pace, speeding up the circulation of the blood to wherever it may be needed.

## What are Heart Disease ?

Heart diseases are diseases of the heart and the blood vessel system within the heart. Many people are surprised to learn that there many different heart diseases. In fact, there are over 50 types of heart diseases, the most common being coronary artery disease. This confusion may stem from the fact that coronary artery disease is often referred to simply as "heart disease."
Heart diseases fall within the broader category of cardiovascular diseases, which are conditions that not only affect the heart, but also the blood vessel system (arteries, capillaries, and veins) within a person's entire body, such as the brain, arms, legs, and lungs. "Cardio" refers to the heart "vascular" refers to the blood vessel system.
Some people are born with heart diseases (such a disease is known as a congenital heart disease) others develop during a person's lifetime. Because there are so many types of heart diseases, it may be helpful to categorize them based on the areas of the heart or blood vessel system they affect, such as:
* Arteries and veins
* Electrical system
* Heart chambers
* Heart muscle itself
* Heart valves
* Heart lining

## Keeping your Heart Healthy

When yout heart is strong and healthy, your whole body benefits. When it is sick, the whole body suffers. That is why it is so important for you to take care of your heart, for upon its condition will depend your ability to get the very best out of life. Now if you will place your hand on your chest toward the left side, you will feel the great throbbing center at work. That is your heart. Its function is to move the living stream of blood through all parts of your body, feeding all the cells and removing all the waste materials. If your heart should fail, your whole transportation system would breakdown. It is important for you to ask yourself whether you are giving your heart all the care that it deserves.

## Circulation of blood through the heart

The heart is a large muscular organ which constantly pushes oxygen-rich blood to the brain and extremities and transports oxygen-poor blood from the brain and extremities to the lungs to gain oxygen. Blood comes into the right atrium from the body, moves into the right ventricle and is pushed into the pulmonary arteries in the lungs. After picking up oxygen, the blood travels back to the heart through the pulmonary veins into the left atrium, to the left ventricle and out to the body's tissues through the aorta.

## How does the heart work ?

The heart is actually a muscle that works like a pump in distributing blood throughout the body. The heart has four chambers. The two at the top are the left and right atria and the two at the bottom are the left and right ventricles. Blood vessels lead in and out of these chambers.
Oxygenated blood from the lungs flows into your heart and is then pumped out to the rest of your body. Once the blood has delivered the oxygen to the tissues of the body, it returns to your heart and gets pumped back out to the lungs where it will be re-oxygenated.

## How does blood flow through the heart?

Your heart muscle is a very efficient pump that delivers blood, oxygen and nutrients to your body.
The heart has four chambers - two on the right and two on the left. Both sides of the heart work together. The right side pumps blood into the lungs and the left side pumps blood into the organs and tissues of your body.
After your blood flows through the body, its life-giving oxygen and nutrients have been depleted. To replenish the oxygen and revitalize the blood, it must pass through the heart and then into the lungs again.
Right side: First the oxygen-depleted blood enters the heart through two large veins, the inferior and superior vena cava and then flows into the right atrium. From the right atrium, it passes through the tricuspid valve and then into the right ventrical. The blood is then pumped through the pulmonary valve and into the lungs.
Once in the lungs, carbon dioxide is removed and oxygen is added to the blood.
Left side: The pulmonary vein empties oxygen-rich blood, from the lungs, into the left atrium. From here, the blood flows from your into your left ventricle through the open mitral valve and finally, it is pumped through the aortic valve into the aorta - the blood vessel that feeds all of the other parts of your body.
When the ventricles are full, the mitral and tricuspid valves close. This prevents blood from flowing backward into the atria while the ventricles contract or Pump. This pattern is repeated continuously throughout your life, causing blood to flow continuously to the heart, lungs and other parts of the body.

## How does the heart beat?

The atria and ventricles work together by alternately contracting and relaxing to pump blood through your heart. The heartbeat is triggered by electrical impulses that travel down a special pathway through your heart. The electrical system of your heart is the power source that makes this beating possible.

## What and where are the coronary arteries?

The heart requires oxygen to function properly. But the blood that is pumping through the heart does not supply oxygen to the heart muscle itself. Special blood vessels attached to the outside of the heart, called coronary arteries, supply the heart with oxygen and nutrients needs. Three major arteries and a number of smaller vessels are designed to perform this function.