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How the structure of the heart allows it to function

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Introduction

How the structure of the heart allows it to function Every cell in the body requires a supply of oxygen and food, luckily, that's exactly what the blood does, providing a transport medium to deliver critical supplies and also to remove harmful waste products to the cells. However, without a pump, blood is next to useless if it cannot get to the cells in the first place. The role of the heart is to pump blood around the body. It has to do this about 70 times a minute, 60 minutes an hour, 25 hours per day, from the day your were born to the day you die. Therefore, the heart has to be efficient at pumping about 4300 gallons of blood each day, and respond according to the body's metabolic rate. ...read more.

Middle

This feature is found in a 'double circulation' system, where the blood goes through the heart twice, for every 'lap' around the body. The top 2 chambers are the left and right atria, and these are used to receive blood from the veins. The right atrium receives blood from the superior vena cava (deoxygenated blood from the head), and the inferior vena cava (deoxygenated blood from the body). Both venae cavae have valves to maintain a one-way flow of blood, this prevents blood back flowing due to gravity and reduced pressure in the veins. As the atria fills up with blood, the heart goes in atrail systole, where the atria contract and the blood is forced through the atrio-ventricular valves (tricuspid in the right hand side/bicuspid in the left hand side) ...read more.

Conclusion

Instead, the heart is supplied with its own oxygen and food from the coronary arteries, which cover the entire heart. The two major coronary arteries, (the right coronary artery and left coronary artery) branch off the aorta, which then divides into several smaller arteries that goes into the cardiac muscle and supplies the heart with blood. What also makes the structure of the heart so unique is the muscle, which makes up this pump. Cardiac muscle differs from the rest of the body because it is myogenic. This means, that the muscle naturally contracts and relaxes without any instructions from the brain. Special 'pacemaker' cells in the SAN (Sinoatrial Node) co-ordinate with AVN (Atrio-ventricular node) cells to create a controlled, regular cycle of contractions of the myogenic cardiac muscle. This is what makes the cardiac cycle. ...read more.

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