P3 Outline the Gross Structure and Function of All the Main Body Systems

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P3 Outline the gross structure and function of all the main body systems Cardiovascular - Heart The heart is a muscular hollow organ and is the size of an adults closed fist. It is located in the thoracic cavity between the lungs and protected by the rib cage. The heart is a double pump, each side consisting of a muscular upper chamber (the atrium) and a lower chamber (the ventricle). (Stretch B, 2010, P199) The heart is split into 4 different sections, the right side (tricuspid) of the heart pumps deoxygenated blood from the veins to the lungs for oxygenation. The left side (bicuspid) pumps oxygenated blood from the lungs to the body; the left chamber has a bigger muscular wall than the other chambers and is stronger, so it is able to pump the blood the whole of the body including the head and neck, as it is against the force of gravity. The two sides are separated by a septum. The heart also contains many veins and arteries. Blood is forced up into the Aorta (one of the large arteries) the Aorta splits into two separate parts, one goes up to the head and brain (upper part of the body) and one goes down (to the lower part of the body) Blood travelling around the body is called ‘systemic circulation’. The blood from these arteries feeds the organs and systems (cells & tissues). Once the blood has given up all its oxygen it makes its way back through the heart, through the veins. Blood from the lower part of the body enters the heart through the inferior vena cava. Blood from the top of the body enters the heart through the superior vena cava. Blood only flows in one direction through the heart; the two values (bicuspid & tricuspid) ensure that this happens. When blood ends up in the right atrium, its passed down through the tricuspid value and into the right ventricle, the right ventricle only has to deliver blood a short distance – to the
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