Function Of The Heart Essay

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Explain the function of the heart and the structure of arteries, veins and capillaries.
Referring to Louise Tucker 5th edition, the heart is an organ that pumps blood through the body via the circulatory system, supplying nutrients and oxygen to the tissues and removing carbon dioxide and other waste products.
According to Louise Tucker arteries are thick walled, hollow tubes with a fibrous outer covering, a middle layer of muscle and elastic tissue.
The functions of arteries are:
• Carry oxygenated blood away from the heart to the rest of the body
• Transport nutrients e.g. iron, zinc
• Main artery is the aorta
Structure:
• Lumen, small passage
• Thick, muscular and elastic walls
Veins have three layered walls, their walls are much thinner,
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Ventricle contraction – systole and atrial relaxation – diastole: The AV node receives an electrical signal which is passed onto the cardiac muscle of the ventricles causing them to contract (systole), the bicuspid and tricuspid vales close and the semilunar valves open allowing blood to pass out of the heart via the aorta and pulmonary artery.
Basically, blood enters the heart via the vena cava and pulmonary vein. The pacemaker send electrical signals which control the cardiac cycle. The atria contracts, valves open and blood is pushed into the ventricles. The ventricles then contract, the valves between the atria and ventricles close and the blood is pumped into the aorta and pulmonary artery.
Explain the term blood pressure and describe the role it plays in the circulatory system. Describe the conditions high and low blood pressure.
According to Blood Pressure UK, when your heart beats it pumps blood around your body to give it the energy and oxygen it needs. As the blood moves, it pushes against the sides of the blood vessels. The strength of this pushing is known as blood pressure. If your blood pressure is too high it puts extra strain on your arteries and your heart. Blood pressure is recorded as two numbers, systolic pressure - as the heart beats and diastolic pressure - when the heart
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