The Heart



The Heart has 4 chambers joined together to make one large block of muscle


The Heart lies in the Thoracic Cavity between the lungs


The heart acts as a muscular pump which keeps the blood moving around the body through the circulatory system.


The Heart consists of 2 fused pumps which pump either oxygenated blood to the body or deoxygenated blood to the lungs


The Heart is divided again into 2 more components the Right and Left Atrium and the Right and Left ventricle


Pumping of Blood


Blood is pumped in 2 stages.

Stage One- The Atria pump blood into the ventricles

Stage Two- The ventricles then pump blood to the lungs(the right ventricle) or round the rest of the body(the left ventricle). The left ventricle has a thicker and more muscular wall than the right ventricle, because it has more work to do



In a resting adult human it beats about 70 times per minute and will complete 2.5 million beats in an average lifetime




The Heart Valves keep the blood moving in the correct direction and prevent back-flow.


There are 4 main valves


1)   Bicuspid- This the valve between the left atrium and the left ventricle

2) Tricuspid- This is the valve between the right atrium and right ventricle

3) Aortic semilunar- This is the valve between the left ventricle and the aorta

4)  Pulmonary semilunar- This is the valve between the right ventricle and the pulmonary artery.

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