7475591
Description
Mind Map by Lauren Garner, updated more than 1 year ago
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Created by Lauren Garner
almost 8 years ago
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The Cardiac Cycle
- In the left side of the heart:
- 1) Blood drains into left atrium along
the pulmonary vein.
- 2) As blood pressure raises in left atrium
the atrioventricular valves are forced
open.
- 3) Contraction of left atrial muscle (left atrial
systole) forces more blood through the valve.
- 4) After left atrial systole (muscle
contraction), the left ventricular
muscles start to contract. This is
called left ventricular systole.
- 5) This action forces the left
atrioventricular valve to close. It opens
the semi-lunar valve in the mouth of the
aorta, and the blood then leaves the left
ventricle along the aorta.
- 5) This action forces the left
atrioventricular valve to close. It opens
the semi-lunar valve in the mouth of the
aorta, and the blood then leaves the left
ventricle along the aorta.
- 4) After left atrial systole (muscle
contraction), the left ventricular
muscles start to contract. This is
called left ventricular systole.
- 3) Contraction of left atrial muscle (left atrial
systole) forces more blood through the valve.
- 2) As blood pressure raises in left atrium
the atrioventricular valves are forced
open.
- Same steps are repeated on the
right side at the same time.
- 1) Blood drains into left atrium along
the pulmonary vein.
- Phase 1) Atrial Systole
- Phase 2) Ventricular Systole
- Phrase 3) Distole
- 3) Diastole occurs when atria and ventricles relax. Elastic recoil of
the heart walls in relaxation lower the pressure in atria and
ventricles. Blood under higher pressure in the pulmonary arteries
and aorta is drawn back into ventricles, closing the semilunar
valves and preventing further backflow into ventricles. Coronary
arteries fill during diastole. Low pressure in atria helps draw blood
into the heart from the veins.
- 3) Diastole occurs when atria and ventricles relax. Elastic recoil of
the heart walls in relaxation lower the pressure in atria and
ventricles. Blood under higher pressure in the pulmonary arteries
and aorta is drawn back into ventricles, closing the semilunar
valves and preventing further backflow into ventricles. Coronary
arteries fill during diastole. Low pressure in atria helps draw blood
into the heart from the veins.
- 2) Atrial systole is followed up by ventricular systole. Ventricles
contract from base of heart upwards - increases pressure in
ventricles. The pressure forces open semilunar valves and
blood is pushed up and out through pulmonary arteries and
aorta. Pressure of blood against atrioventricular valves closes
the valves and prevents backflow of blood into atria.
- Phrase 3) Distole
- 1) Blood returns to heart under low pressure. Blood flows into left and
right atria from the pulmonary vein and vena cava. As the atria fill,
increased blood pressure against atroventricular valves pushes them
open. Blood leaks into ventricles. Atria walls contract - more blood is
forced into ventricles.
- Contraction of atria is known as atrial systole.
- Phase 2) Ventricular Systole
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