Cardiac Cycle Flashcards
1
Q
what are the 4 phases of the cardiac cycle
A
- ventricular filling
- isovolumetric contraction
- ejection
- isovolumetric relaxation
2
Q
what does systole mean
A
contraction
3
Q
what does diastole mean
A
relaxation
4
Q
what are the names of the 2 sub phases in ventricular filling
A
atrial diastole and atrial systole
5
Q
what happens during atrial diastole
A
- heart relaxed
- AV (mitral valve) is open
- blood flows passively into ventricle
- SL (aortic) valve is closed
6
Q
what happens during atrial systole
A
- ventricle remains in systole
- atrium contract
- blood is forced into the ventricle to complete ventricular filling
7
Q
what happens during isovolumetric contraction
A
- atrial systole ends; ventricular systole begins
- intraventricular pressure rises
- AV valve closes (first heart sound, S1 - lub)
- ventricle is a completely closed chamber
8
Q
What happens during ejection
A
- ventricle continues to contract
- intraventricular pressure surpasses pressure in aorta
- SL valve opens
- blood is ejected forcefully from the ventricle into the aorta
- atrium is relaxed and filling with blood
9
Q
what happens during isovolumetric relaxation
A
- ventricular diastole begins
- pressure in left ventricle falls below pressure in aorta
- SL valve closes (second heart sound, S2 - dub)
- ventricle is a completely closed chamber
- when atrial pressure increases above intraventricular pressure, AV valve opens
