cardiac cycle Flashcards
define systolic pressure
highest pressure in the aorta during contraction
~120
define diastolic pressure
lowest pressure in the aorta during relaxation
~80
define mean arterial pressure
MAP
1/3 of the way between diastolic and systolic pressure
~90-95
diastolic + 1/3 of systolic
define pulse pressure
difference between systolic and diastolic pressure
~40
define end diastolic volume
EDV
volume in the heart at the end of diastole
~140ml
define end systolic volume
ESV
volume in the heart at the end of systole
~60ml
define stroke volume
SV = EDV - ESV
~80ml
main determinant is the size of the person
define ejection fraction
EF = SV/EDV
~2/3
clinically more useful than SV
reduces with poor health
what does the A wave represent
atrial contraction
slight increase in pressure
what does the C wave represent
ventricular contraction
rise in pressure then quickly falls
pressure released when aortic valve opens and blood escapes out
what does the V wave represent
blood accumulates in atrium during ventricular systole
gradual increase in pressure
mitral valve opens and blood moves through to ventricles
pressure inside atria falls
define isometric contraction period
the ventricles are contracting but volume remains the same
rapid/slow ejection phase
during systole
rapid first then slower
rapid/slow filling phase
during diastole
rapid first then slower
if HR increases, filling phase decreases
>140bpm cuts into rapid filling phase which has a big impact
what occurs during late diastole
both sets of chambers are relaxed and the ventricles fill passively
