Lecture 2 Cardio Flashcards
Cardio/GI (53 cards)
2 phases of the cardiac cycle?
systole and diastole
what happens during diastole?
the ventricles are relaxing and filling with blood from their respective atria
What happens during systole?
The cardiac ventricles are contracting and ejecting blood into the aorta and pulmonary arteries
Blood flows from atria to ventricles when…
the AV valves (mitral and tricuspid) are open d/t a pressure gradient where the A>V
Blood flows out of the ventricles across the aortic and pulmonic valves when..
the BP is higher in the ventricles than their corresponding outflow tracts.
There are 2 filling phases in diastole
rapid and slow
Describe the rapid filling phase
Early in diastole (after the ventricle relaxes and the ventricular pressure is less than atrial - mitral valve has opened passively), the pressure gradient is large and ventricular filling is rapid
Describe the slow filling phase
As diastole progresses, the pressure gradient diminishes and ventricular filling progressed more slowly.
What is the atrial contraction phase?
the L atrium contracts and pushes an additional small amount of blood into the ventricle (as a result of the electrical activity from section 1)
What is the total volume of blood contained in the ventricle at the end of atrial contraction
end-diastolic volume (EDV)
After atrial contraction, ventricular contraction occurs. The ____valve closes to stop backflow of blood.
mitral
For a time after the mitral valve closes, the aortic valve is still closed, because aortic pressure is still higher than ventricular but as the ventricular contraction occurs, the ventricular pressure rapidly increases because both valves are closed and the walls of the closed chamber are contracting. What is this phase called?
isovolumic contraction phase
2 Phases of ventricular ejection
rapid and slow ejection phases
Describe the rapid ejection phase
when ventricular pressure exceeds aortic pressure and the aortic valve opens, the initial blood flow is rapid
Describe the slow ejection phase
When the blood flow from the ventricle diminishes as the pressure gradient diminishes.
As ventricular relaxation begins, the ventricular pressure falls. This causes blood to try and backflow but this movement of blood toward the ventricle causes ___
the aortic valve to close.
Ventricular relaxation progresses until the ventricular pressure is ___
again less than the atrial pressure and the mitral valve opens. This starts the cycle all over again.
The period of time between the closing of the aortic valve and opening of the mitral valve is called
isovolumic relaxation phase
The amount of blood contained in the ventricle at the end of the ejection phase is the
end systolic volume - ESV
The amount of blood contained in the ventricle at the end of the atrial contraction phase is the
end diastolic volume -EDV
The difference between the end diastolic volume and the end systolic volume is ____
stroke volume - SV
SV= EDV-ESV
What is the ejection fraction?
the amount of blood ejected during a contraction (SV) expressed as a percentage of the total amount of blood contained in the ventricle at the end of diastole (EDV)
EF = SV/EDV
What is typical EF (in a “normal” individual)?
60%
The decrease in aortic pressure during diastole (120 mmHg - 80 mmHg) is the result of
blood leaving the aorta and being distributed to the peripheral vascular network.
