Taylor- Cardiac Output Flashcards
3 ways the body can alter stroke volume
contractility, aortic pressure, venous pressure
cardiac output of the heart=
stroke volume x HR
cardiac output of vasculature=
MAP/SVR
increasing volume increases _____ of contraction
strength (Starling’s law)
A, B, C, D
ejection loop
A: diastolic filling
B: isovolumetric contraction
C: ejection
D: isovolumetric relaxation
ejection fraction=
SV/LVEDV
normal ejection fraction
above 0.50
real ejection loop has rounded top since bp changes during ejection
auxotonic beat
increased contractility does what to stroke volume; what about LVESV
increases it (can eject more blood out); LVESV is lower
decreasing contractility does what to SV and LVESV
decreases SV; LVESV is higher (less blood ejected)
raising aortic pressure does what to emptying of the heart (increases afterload)
opposes emptying of the heart
increasing aortic pressure does what to SV and LVESV
SV decreases; LVESV higher (can’t empty contents of heart well)
lowering aortic pressure (reducing afterload) allows ventricle to do what
empty more completely
decreasing aortic pressure does what to SV and LVESV
increases SV; LVESV lower
increasing venous pressure does what to SV and LVEDV
increases SV; LVEDV is higher (increased preload)
decreasing venous pressure does what to SV and LVEDV
SV lower; LVEDV lower
how much arterial pressure the heart works against during systole
afterload
how hard the heart contracts during systole
contractility
how much blood fills the heart from venous side during diastole
preload
fundamental determinant of stroke volume and cardiac output; determines preload
central venous pressure
what happens to LVEDV and SV when ventricular hypertrophy is present
LVEDV decreased due to reduced diastolic compliance; SV decreases
what happens at high HR’s to CO and why
decreases; less filling time b/t beats
why does CO increase with increasing HR during EXERCISE
sympathetics speed up both contraction and relaxation (more diastolic filling time)
what happens if heart is
NOT pumping
no flow and bp constant at 7mmHg