The Cardiac Cycle Flashcards
What occurs in late diastole?
Both sets of ventricles are relaxed and fill passively
What happens during atrial systole?
Atrial contraction injecting blood into ventricles
What happens during isovolumic ventricular contraction?
- First phase of ventricular contraction - Pushes AV valves closed but doesn’t exceed pressure to open
What happens during ventricular ejection?
- Ventricular pressure exceeds pressure in the arteries - Semilunar valves open and blood is ejected
What happens during isovolumic ventricular relaxation?
- Ventricles relax - Pressure drops - Blood tries to flow back into the ventricles and this action snaps the semi lunar valves shut
What is the pulse pressure?
Difference between diastole and systole
How is the mean arterial pressure usually calculated?
Diastolic pressure + 1/3rd of systolic pressure
Why is only 1/3rd of systolic pressure added to diastolic to calculate the MAP?
Most time is spent in diastole
What should ejection fraction be in a health individual?
2/3rds
What does EDV stand for?
End diastolic volume
What two phases is systole split into?
- Rapid ejection - Slow ejection
What occurs in the rapid phase systole?
- Most of the blood is ejected in this phase
What occurs in the slow ejection phase?
The rest of the blood is ejected
Why does doubling the HR have little effect on diastolic volume?
The heart is usually full and ready to pump again in half the total diastolic time
STUDY THE FOLLOWING DIAGRAM
What is the name of this type of diagram?
Pressure volume loop
What happens at A on the diagram?
Mitral Valve opens
What causes the mitral valve to open at A?
Atrial pressure excedes ventricular pressure
What happens at B on the PV loop?
Mitral valve closes in response to ventricular contraction
What happens at C on the PV loop?
Aortic valve opens in response to ventricular pressure exceeding aortic pressure
What happens at D on the PV loop?
Aortic valve closes
