The Cardiac Cycle Flashcards
Pressures in the cardiac chambers
Are constantly changing throughout the cardiac cycle
what occurs in early diastole for both left and right ventricles?
Pressure drops to 0mm Hg
pcw
pulmonary capillary wedge
when is pcw used
intensive care setting using a swan-ganz catheter
Right atrium average pressure
1-5mm Hg
left atrium average pressure
2-12mm Hg
Right ventricle average pressure systole
15-30mm Hg
Right ventricle average pressure diastole
1-7mm Hg
Pulmonary Artery average pressure systole
15-30mm Hg
Pulmonary Artery average pressure diastole
4-12
Left ventricle average pressure systole
90-140
left ventricle average pressure diastole
5-12mm Hg
Aorta pressure systole
90-140mm Hg
Aorta pressure diastole
60-90mm Hg
Cardiac Output
Amount of blood pumped by each ventricle in 1 minute
what is cardiac output the product of?
Stroke volume and heart rate
what is the average cardiac output?
4-8 liters per minute
As cardiac output increases
blood pressure increases
Stroke volume
The volume of blood ejected by the ventricles with each contraction
Any effect on SV or HR
affects the cardiac output
Preload
the degree that the muscle fiber stretches before contraction
Preload is affected by what?
ventricles ability to stretch and relax
Afterload
Aortic arterial pressure and vascular resistance the ventricle must overcome to eject blood or any resistance against which the ventricle must pump against to eject its volume
Blood flow velocity depends on what?
Many factors
- size and shape of the vessel/chamber it is traveling through
- wall characteristics
- timing within the cardiac cycle
- flow rate
- viscosity of blood
Flow starts with what?
uniformly with similar profiles, giving a flat laminar appearance
most of the flow is traveling how fast?
traveling at the same velocity as the laminar flow
where are the flow velocities the highest?
toward the middle of a vessel
where can flow become turbulent
travels through an area of obstruction or smaller surface area
