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Heart as a pump
It's the organ that moved the blood around the body

Its four chambered muscular and sits in the chest protected by the ribs and the
sternum. Its contained in a tightly fitting membrane called the pericardium.

Its divided into four chambers, right side is separate from…

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Cardiac Cycle

1. Right atrium receives blood from the veins. Pressure builds up, and
tricuspid valve opens and blood begins to seep into ventricle. When atrium
is full its contracts, forcing the blood into the ventricle. (atrium has thin
walls because it receives blood at low pressure)

2. The right…

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Atrium has thin walls because it receives blood at low pressure)

The tendentious cords make sure the valves are not inside out by the great
pressure when ventricles contract

The wall of the left side of the heart is thicker than the right, because right side
pumps blood to the…

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The contraction of the heart is called a systole

Systole is divided into atrial systole, when the atria contact forcing blood into
ventricles, and ventricular systole when the ventricles contract.

Between contractions the heart relaxes and the atria fill with blood. This stage is
called a diastole.

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Pressure graph
At the start of the cycle, the pressure in the atrium and ventricle is almost zero
as the muscles are relaxed.

As the muscles of the atrium contract, the pressure rises. The pressure also
rises slightly during atrial systole as the blood is pushed through the
atrioventricular valves…

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Blood pressure

Blood pressure is a measure of hydrostatic force of the blood against the walls of
blood vessel.

There is friction between the blood and the walls of vessels. This friction is called
the peripheral resistance and it slows down the flow of blood.

Little pressure is lost in…

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Formation of tissue fluid

the formation of tissue fluid assist in delivery of nutirents to all cells and
removal of waste products.

the hydrostatic pressure generated drives out fluid from the capillaries

arterial end of a capillary is under high pressure. this forces the fluid and small
molecules in plasma…

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