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
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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