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What signifies the end of isovolumetric relaxation?
Press to flip
The opening of AV valves as ventricular pressure falls below atrial pressure.
What does the QRS complex on an EKG indicate in the cardiac cycle?
Ventricular depolarization.
During mid to late ventricular diastole, what causes blood to flow passively from the atria to the ventricles?
Atrial pressure is greater than ventricular pressure, causing the AV valves to open.
What EKG component represents ventricular repolarization during the cardiac cycle?
The T wave.
What is characteristic of isovolumetric contraction?
All valves are closed, ventricular volume is constant.
What does the P wave on an EKG represent during the cardiac cycle?
Atrial depolarization, pushing the remaining 20% of blood into the ventricles.
What is the dicrotic notch and when is it observed?
A slight increase in aortic pressure due to semilunar valve closure, observed during isovolumetric relaxation.
What are the key phases of the cardiac cycle?
Mid to Late Ventricular Diastole, Isovolumetric Contraction, Mid to Late Ventricular Systole, Isovolumetric Relaxation.
Which valves are open during the phase of ventricular filling?
The AV valves (tricuspid and mitral) are open.
During ventricular ejection, what pressure relationship allows for the ejection of blood?
Ventricular pressure is greater than arterial pressure, opening the semilunar valves.
What is the average duration of a single cardiac cycle?
0.8 seconds
What is responsible for the second heart sound, 'dub'?
The closing of the semilunar valves.
What heart sound is associated with the closing of the AV valves?
The first heart sound, 'lub'.
What role do semilunar valves play during mid to late ventricular systole?
They open, allowing blood to be ejected into the pulmonary trunk and aorta.
How does the atrial pressure compare to the ventricular and arterial pressures during early ventricular diastole?
Atrial pressure is less than arterial pressure but can be greater than ventricular pressure, allowing the initial opening of AV valves.
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