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The Heart

The Heart. Alexis, Sarah and Shona. The Function Of The Heart. The heart is a double muscular pump One side of the heart pumps blood to the lungs. The other pumps blood to the rest of the heart.

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The Heart

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  1. The Heart Alexis, Sarah and Shona

  2. The Function Of The Heart • The heart is a double muscular pump • One side of the heart pumps blood to the lungs. The other pumps blood to the rest of the heart. • We need the heart to pump blood around the body as diffusion is too slow a process to carry substances in and out of cells. • On average, the heart normally does 70m beats per minute in a young person undergoing strenuous exercise, the heart can beat 200 times a minute; but can beat as slow as 40 times in a resting athlete per minute.

  3. Structure Of The Heart • There are 4 chambers of the heart: • The Left Atrium • The Right Atrium • The Left Ventricle • The Right Ventricle • The Right atrium receives deoxygenated blood from all parts of the body via two main veins called the vena cava. • The deoxygenated blood passes through the right ventricle and then leaves the heart through the Pulmonary Artery which goes into the lungs. • Following oxygenation in the lungs, blood returns to the heart by the Pulmonary Veins and enters the Left Atrium. From there it flows from the Left Ventricle and leaves the heart by the Aorta.

  4. The Valves Of The Heart • The heart has 4 valves. • All valves prevent the backflow of blood. • 2 of them are called the Atria-Ventricular (AV) • These are situated between the Atria and the Ventricles. Each AV valve has its own name. Right side =Tricuspid valve Left side = Bicuspid Valve • The AV valve allows the blood to flow from the atria to the ventricles and prevent any backflow from the ventricles back to the artia.

  5. The Valves Of The Heart • The other 2 valves are the semi-lunar (SL) Valves. • They are situated at the start of the Pulmonary Artery and the Aorta. • These valves open during contractions allowing blood to flow into the arteries. • When blood pressure in the arteries is greater than the blood pressure in the ventricles they close preventing backflow. Valves ensure that blood is only able to flow in one direction through the heart.

  6. Oxygenated blood from the lungs ready to be pumped around the body The blood is returned from the body into the lungs to become oxygenated Oxygenated blood returns from the lungs to then being pumped around the body The wall of the left ventricle is particularly thick and muscular ad it is required to pump blood all around the body. The wall of the right ventricle is less thick as it only pumps blood to the lungs

  7. Coronary Arteries • The heart wall is made up of respiring muscles. • To keep these cells alive there needs to be a continuous supply of oxygenated blood. • The fist 2 branches of the aorta are the left and right Coronary Arteries. • These are spread all over the surface of the heart and divide into an enormous number of tiny branches. • The branches lead to a dense network of capillary beds in the muscular wall of the heart. • The arrangement allows rapid diffusion of oxygen and food into the actively respiring Cardiac muscle tissue. • Coronary veins return DEOXYGENATED blood from the heart wall to the vena cava.

  8. Coronary heart disease • This term refers to any disease that results in restriction or blockage of the coronary blood supply to part of the hearts muscular wall. • The blockage deprives the affected part of the oxygen and can result in the death of the muscle cells. • If a small region of the heart is affected the person can make a satisfactory recovery. • If a large part is affected the person could die instantly. • Coronary heart disease is the most common form of premature death in many developing countries.

  9. Games/ Videos http://interactivehuman.blogspot.co.uk/2008/10/heart-heart-information-cardiovascular.html http://www.bbc.co.uk/learningzone/clips/heart-function-and-health/1466.html

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