Essay on Obesity and the Cardiovascular System

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Obesity and the Cardiovascular System

The main function of the cardiovascular/circulatory system is to continuously pump blood around the body. It consists of the heart, arteries, veins and the capillary network of arterioles and venules. The capillary network is vast consisting of 62,000 miles of blood vessels. Any blockages in cardiovascular system can be very dangerous to our health, even fatal.

The heart, the body's pump, has 2 compartments separated by a septum. Each compartment contains 2 chambers, atrium and ventricle. The right side pumps de-oxygenated blood to the lungs (pulmonary circulation) and left side oxygenated blood to all other organs and tissues (systemic circulation).
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The atrioventricular valves are pushed open when blood enters ventricles from atrium. When ventricles contract these valves are forced shut by the pressure of blood in the ventricle and outlet valves, pulmonary and aortic valves open, forcing blood out to the lungs and body. When ventricles relax the opposite occurs.

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There is one artery on either side of the heart, the pulmonary on the right and the aorta on the left. These are the vessels that carry blood away from the heart. Blood leaves the left ventricle (systemic circulation) through the aortic artery (arteries carry blood at high pressure so artery walls have to be thick, strong and elastic) which divides into progressively smaller branches to the smallest of the arteries, arterioles. The arterioles branch into a vast number of tiny capillaries. Capillaries deliver food and oxygen direct to the body tissues and take away waste products, which is why capillaries are only one cell thick to allow substances to diffuse easily. Capillaries are too small to see with the naked eye.

The capillaries come together to form the venules, the venules come together to form the veins which carry the used blood back through the pulmonary circuit leading to the superior and inferior cava and back to the heart to be oxygenated and so the circuit continues.

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