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The Circulatory system. Human circulatory system. Key features. Blood vessels. What the blood carries. The Heart. The journey of blood. Journey of blood contd. Structures of the heart. Left and right side separated by solid septum to prevent mixture of oxygenated and deoxygenated blood
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Structures of the heart • Left and right side separated by solid septum to prevent mixture of oxygenated and deoxygenated blood • Left wall much thicker as it has to pump blood all round body. (right wall only pumps to lungs) • In baby septum, is open because it gets oxygen from placenta not lungs. Septum closes at birth • Failure to do so leads to hole in the heart or blue baby.-
Heart beats • Volume and speed can vary dependent upon need. Regulated by the nervous system. • On average about 5.25L pumped per minute – approximately your total body volume. An electrocardiogram showing the impulses of a normal heart beat. P shows the initiation of the contraction from the SA node R shows the initiation of ventricular contraction
Cardiac cycle Systole refers the period of contraction- High pressure Diastole refers to the period when the chambers of the heart are relaxed – low pressure
These are not correct! • Blood flows down one leg and up the other; • Three kinds of blood vessels are arteries, vanes and caterpillars