stages of blood flow

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  • Created by: Leigh. x
  • Created on: 12-10-12 10:49

Phase 1- ATRIA SYSTOLE

Blood travels back to the heart. This is because of skeletal and gaseous exchange muscles as we move and breathe

Blood is under low pressure whilst flowing into the left and right atria from the pulmonary veins and vena cava

as the atria fill the pressure against the atrioventricular valves pushes them to open

blood flows into the ventricles

the atria walls contract forcing more blood into the ventricles

ATRIA SYSTOLE

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Phase 2-VENTRICLE SYSTOLE

Immediately after atria systole is ventricle systole

Ventricles contract from the base of the heart upward

This increses the pressure in the ventricles

This allows the blood to be pushed up and out through the arteries

The pressure of blood against the atrioventricular valves closes them- preventing backflow into the atria

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Phase 3-DIASTOLE

both atria and ventricles relax

elastic recoil of the relaxing heart walls lower pressure in them

blood under higher pressure in the arteries is drawn back to the ventricels

furthur backflow is prevented by closed semilunar valves

low pressure in the atria allows blood to flow into the heart from the veins

both atrioventricular and semi lunar valves are closed

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Circulation

The heart has its own circulatory system because

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