Cardio: Cardiac Cycle

Front 1

systole

Back 1

-active phase: ventricle contracts and blood is ejected into the circulation
- both AV valves are closed, preventing backflow into the atrium
- both semilunar valves are open, allowing blood to leave the ventricle

Front 2

diastole

Back 2

-passive phase: ventricles relax and fill with blood
- both semilunar valves closed, preventing backflow into the ventricles
- both AV valves are open to allow blood to flow

Front 3

atrial systole and diastole

Back 3

-systole and diastole usually refer to ventricles
- atria also have systole and diastole, but they are shorter and begin/ end before the related ventricular actions

Front 4

cardiac cycle gen

Back 4

-sequence of mechanical events of a whole heartbeat
-diastole: atria and ventricles are relaxed and blood returning through the large veins flows through the open AV valves and into the ventricles
- in order to complete filling the ventricles, you must contract atria

Front 5

1. cardiac cycle

Back 5

1. atrial systole
2. ventricles still relaxed
3. atrial contraction completes filling of the ventricles

Front 6

2. cardiac cycle

Back 6

1. ventricular systole begins
2. BP rises
3. all valves closed
4. isovolumetric contraction

Front 7

3. cardiac cycle

Back 7

1. ventricular pressure higher than aortic/ MPA pressure
2. ejection

Front 8

4. cardiac cycle

Back 8

1. ventricular diastole begins
2. BP falls
3. all valves closed
4. isovolumetric relaxation

Front 9

5. cardiac cycle

Back 9

1. atrial pressure higher than ventricular pressure
2. AV valves open
3. passive filling

Front 10

Pressure during diastole

Back 10

-ventricular P slightly lower than atrial

Front 11

Pressure during systole

Back 11

-during ventricular contraction, ventricular P rises steeply and exceeds the atrial P:
1. AV valves close

Front 12

P and aortic valve

Back 12

1. closed: as long as ventricular P is lower than the aortic pressure, end of systole (=diastole)
2. open: when ventricular P exceed aortic P, blood ejected

Front 13

P and AV valves

Back 13

-during decrease in ventricular P all valves are closed
...until it falls below atrial P and AV valves open

Front 14

End diastolic P

Back 14

maximum volume of entire cardiac cycle
- because ventricle keeps filling up to the very end of diastole

Front 15

End systolic V

Back 15

-lowest ventricular blood volume
- at end of systole

Front 16

stroke volume

Back 16

volume of blood ejected during systole
- difference between end-diastolic and end-systolic P