The Function Of The Heart And The Cardiovascular System

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Everyday our bodies need oxygen and different nutrients to function properly but in order to maintain that constancy, our blood has to be constantly moving. And in order for our cells to get transported and get everything they need, the heart needs to be beating. The cardiovascular system makes sure the levels of substances in the blood is constant by transporting these substances as circumstances change. The heart is located in the lower part of the mediastinum between the lungs. Most people think the heart lies on the left side of the body but if the chest was cut in half, two thirds of the heart would be on the left and one third would actually be on the right side of the body. The heart is triangular and roughly the size and shape …show more content…
Contraction of the heart is systole and relaxation is diastole, when the heart beats the stria contract and force blood into the ventricles. Once the ventricles are filled they contract to force the blood out of the heart. Four valves are located at the entrance and exit of ventricles in order to prevent backflow of blood. Two valves that separate the atrial chambers are the AV (atrioventricular) valves. The bicuspid (mitral) valve is between the left atrium and ventricle, the tricuspid is between the right atrium and ventricle. SL (semilunar) valves are between ventricular chambers and large arteries. At the beginning of the pulmonary artery is the pulmonary SL valve and at the beginning of the aorta is the aortic semilunar (“The Heart and Heart …show more content…
One complete cycle lasts 0.8 seconds at the average of 72 beats per minute. Stroke volume is the volume of blood ejected from the ventricles during each beat. The volume of blood pumped by one ventricle per minute is the cardiac output which is 5 liters in a normal resting adult. Valve disorders, coronary blockage or a myocardial infarction can result in a decreased stroke volume and decreased cardiac output which can end in fatigue or in the worse case, death (“The Heart and Heart

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