The Cardiac Cycle Flashcards
(33 cards)
Diastole
Relaxation
Systole
Contration
Late diastole
Both sets of chambers are relaxed and ventricle fill passively
Atrial systole
Atrial contraction forces a small amount of additional blood into ventricles
Isovolumic ventricular contraction
First phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves
Semilunar valves
Pulmonary and aortic valves (artery valves)
AV valves
Atrium-ventricle valves
Ventricular ejection
As ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected
Isovolumic ventricular relaxation
As ventricles relax, pressure in ventricles falls, blood flows back into cusps of semilunar valves and snaps them closed
Systolic pressure
Pressure in arteries during contraction of heart = 120mmHg
Diastolic pressure
Pressure of arteries during relaxation of heart = 80mmHg
Pulse pressure
Difference between systolic pressure and diastolic pressure
Systole diastole ratio
1:2 (1/3 systole, 2/3 diastole)
End-diastolic volume (EDV)
140ml
End-systolic volume (ESV)
60ml
Stroke volume
Difference between EDV and ESV
Ejection fraction
SV/EDV (indicates health of heart)
Dicrotic notch
When aortic valve closes so there is a little increase in aortic pressure and continued decrease in ventricular pressure
a atrial pressure wave is due to
Atrial contraction
c atrial pressure wave is due to
Mitral valve closing and ventricular contraction then aortic valve opening
v atrial pressure wave is due to
Blood accumulating in atrium
Isometric contraction phase
Between mitral valve closing and aortic valve opening
Isometric relaxation phase
Between aortic valve closing and mitral valve opening
Heart sounds are due to
Turbulence when valves open and close
