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The Cardiovascular System

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The Cardiovascular System
The cardiovascular system is made up of the heart, blood vessels and the blood and its main functions include the transportation of blood around the body, protection from invading microorganisms and to prevent blood loss through haemostasis. (Widamaier, et al 2011:5)
One of the main organs of the cardiovascular system is the heart; the heart is made up of four chambers. The blood enters the right atrium of the heart from body through the venae cavae, it then travels though the tricuspid atrioventricular valve into the right ventricle. The blood is then pumped through the pulmonary semilunar valve out of the heart to the lungs using the pulmonary arteries. It is then oxygenated and returns to the left atrium in the pulmonary veins it travels through the mitral atrioventricular valve into the left ventricle and is then pumped out of the heart to the systematic circulatory system passing through the aortic semilunar valve into the aorta. (Widamaier, et al 2011:359)
The heart is situated in the thoracic cavity protected by a sac called the pericardium. The inner heart wall is made up of three layers the outside of the heart wall is called the epicardium this lubricates the heart and prevents friction. The middle and thickest layer of the heart, called the myocardium, is a thick muscular layer built up of cardiac muscle which is responsible for pumping blood. The thickness of the myocardium varies throughout the heart, the atria does not need as much myocardium as the ventricles as the atria only need enough pressure to pimp the blood to the ventricles whereas the ventricles need enough pressure to pump blood to the lungs and the body. The left ventricle has a thicker myocardium layer than the right as the le...

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...njury. (Widamaier, et al 2011:354)
The cardiovascular system is made up of the heart which pumps blood to the lungs through pulmonary circulation, the heart muscle through cardial circulation and the body systems through systematic circulation. It is made up of various chambers and valves and its cycle is controlled by an electrical signal originating in the heart itself. There are various different vessels which control the blood flow throughout the body. Which include high pressure arteries and arterioles originate from the heart. Capillaries which have a semipermeable membrane that allows the exchange of gasses, nutrients and wastes between the blood and the tissues. Also veins which are low pressure and contain valves that prevent backflow. All of these together perform the main functions of the cardiovascular system; protection, transportation and regulation.
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