Heart Essay

RUNNING HEAD : The Heart

The Heart : Knowing it by Heart

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The Heart : Knowing it by Heart

According to the Bible , Where your treasure is , there will your heart be also (Matthew 6 :21 . Indeed , the role of the heart in the body is as valuable as a treasure . As one important muscle in our body , it has a very vital function in our human body . This muscle pumps blood in our body , so that blood could distribute oxygen to other parts of our body Oxygen is needed in

for our organs to function properly

However , the importance of this organ is often overlooked because heart disease is the top cause of death among all over the world . In fact , one of every two men and one of every three women in the United States will develop some form of cardiovascular illness . Each year an estimated one million Americans suffer a heart attack nearly half of them die (Heart Care Strategic Management , June 2001 . Heart-related diss account for almost as many deaths as the combined influenza , pneumonia , AIDS , and all other causes . Globally , heart disease and stroke are responsible for , respectively , 7 million and 5 .5 million deaths (Beaglehole , 25 August 2001

Often said that it is the size of our fist , the heart can be found between our two lungs and slightly to the left of center , behind the breastbone . It rests on the diaphragm , the muscular partition between the chest and abdominal cavity and is made up of four different blood-filled areas , and each of these areas is called a chamber . There are two chambers on each side of the heart : one chamber is on the top and one chamber is on the bottom . The two chambers on top are called the atria .The atria are the chambers that fill with the blood returning to the heart from the body and lungs . The two chambers on the bottom are called the ventricles . Their job is to pump out the blood to the body and lungs . Running down the middle of the heart is a thick wall of muscle called the septum .The septum 's job is to separate the left side and the right side of the heart (ThinkQuest New York City , 2006

According to Encyclopaedia Britannica (2006 , the normal pumping of the heart , or the heartbeat , is caused by alternating contractions and relaxations of the myocardium . These contractions are stimulated by electrical impulses from a natural pacemaker , the sinoatrial (S-A ) node located in the muscle of the right atrium . An impulse from the S-A node causes the two atria to contract , forcing blood into the ventricles Contraction of the ventricles is controlled by impulses from the atrioventricular , or A-V , node located at the junction of the two atria Following contraction , the ventricles relax , and pressure within them falls . Blood again flows into the atria , and an impulse from the S-A starts the cycle over again . This process is called the cardiac cycle Contraction of the...