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How the Heart Works

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Introduction

How the Heart Works Although the heart is often referred to as a symbol of courage and love, it is no more than a muscular pump. From the moment it begins beating to the moment we die the heart works non-stop beating an average of 72 beats per minute, 37,843,200 beats per year and 2,838,240,000 beats per average lifetime1. Like most other pumps the human heart can break down, thus need repair. Heart disease is the leading cause of death in the United States, an amazing 2,000 Americans die of heart disease everyday that's an average of one every 44 seconds2. This is why it is important to know how your heart works, because with even the slightest bit of knowledge as to what is good and what is bad for it you can drastically reduce your risk for heart disease. The human heart weighs approximately 275 grams3 and is about the size of a clenched fist. Although many believe that the heart is located left of the chest, it is actually located perfectly center between the two lungs, protected by the sternum (breastbone), the rib cage, the vertebral column (spine), the scapular (shoulder blade) and the clavicle (collarbone). The human heart is enclosed in a two layered membrane called the pericardium, not only does it anchor the heart to its surrounding structures but prevents the heart from overfilling with blood. The outer wall of the heart is composed of three layers. The outer layer is called the visceral pericardium as the outer layer is in fact the inner layer of the pericardium. ...read more.

Middle

The artery splits up and eventually becomes capillaries which will resemble a filter (permeable layer) only allowing the good and useful substances (food and oxygen) to be obtained by the cells. This process is called diffusion and the fluids that exit the bloodstream have no distinct colour, proving that the membrane only allows certains substances to pass and obviously haemoglobin isn't one of them. Eventually the cells will send waste products such as CO2 into the bloodstream through veins which is how the blood becomes deoxygenated, any remaining fluid that isn't obtained by the cells, ergo seeped all the way through tissue, is obtained by lymph's and temporarily stored in a lymph node and eventually send back into the blood stream once again through veins. The blood travels up slowly and smoothly through the vein as there is very low pressure (some veins even have valves similar to the ones in our heart to prevent the blood from flowing back) and back to the heart through the superior and inferior vena cava. This process of blood flow is repeated countless times and does not stop till you die. How does the heart actually beat automatically? The answer lies in a group of specialized cells found in the natural pacemaker of the heart, the sinoatrial node located near the right atrium. These cells have the ability to generate electrical activity automatically, separating charged particles and spontaneously send them into the left and right atria causing them to contract simultaneously. As mentioned the middle layer of the heart myocardium consists of cardiac muscle, a special kind of fibre not found anywhere else in the body with the ability to conduct electricity. ...read more.

Conclusion

* Congenital heart defects - Heart defects presents from birth, possibly due to a fault during early embryo development * Valve disorders - There are several conditions that can affect the efficient functioning of any of the heart's four valves * Heart murmurs - Unusual heart sounds produced by turbulent blood flow which may be due to a heart valve defect Circulatory and heart-rate disorders - A constant and adequate blood supply is essential for healthy tissues. If a blockage occurs in a blood vessel the tissues will be starved of oxygen causing the tissue damage and in severe cases lead to tissue death. The heart may also be affected if the electrical system is disturbed. * Embolism - An embolus is a fragment of a material that breaks away from its original location which can cause partial or total blockage of a blood vessel * Thrombosis - The partial or total blockage of an artery, vein or even the heart can occur whena blood clot (thrombus) forms due to a circulatory problem * Aneurysm - Abnormal welling of a weakened arterial wall, which results in making the wall bulge out like a balloon * Hypertension - Internal organs can become damaged if not treated due to a high blood pressure * Arrhythmia - An abnormal heart rate of rhythm which is caused by a disturbance in the electrical system So if you wish to keep your heart healthy for the rest of your life do following: 1. Get plenty of exercise 2. Follow a good diet 3. Keep ypur heart clean and drug-free "Be heart smart and have a healthy heart. ...read more.

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