Enter the URL of the YouTube video to download subtitles in many different formats and languages.
The cardiac cycle refers to the sequence of\n
It can be divided into 2 major phases: systole\n
Systole and diastole, when not specified otherwise,\n
Reminders:\n- Blood flows from higher to lower pressure.
- Contraction increases the pressure within\n
- AV valves open when atrial pressures are\n
when the pressure gradient is reversed.
Similarly, semilunar valves open when ventricular\n
pressures, and close when the reverse is true.
The cycle is initiated with the firing of\n
This is represented by the P-wave on the ECG.
Atrial contraction starts shortly after the\n
the atria to increase, forcing blood into\nthe ventricles.
Atrial contraction, however, only accounts\n
at this point, the ventricles are already\n
the ventricles through the open AV valves.
As atrial contraction completes, atrial pressure\n
across the AV valves, causing them to close.
The closing of the AV valves produces the\n
At this point, ventricular DE-polarization,\n
through, and the ventricles start to contract,\n
For a moment, however, the semilunar valves\n
This phase is referred to as isovolumetric\n
ventricular volume is unchanged.
Ventricular ejection starts when ventricular\n
aorta and pulmonary artery; the aortic and\n
This is the rapid ejection phase.
As ventricular repolarization, reflected by\n
to fall and the force of ejection is reduced.
When ventricular pressures drop below aortic\n
close, marking the end of systole and beginning\nof diastole.
Closure of semilunar valves produces the second\nheart sound, S2.
The first part of diastole is, again, isovolumetric,\n
Ventricular pressure drops rapidly but their\n
Meanwhile, the atria are being filled with\n
Ventricular filling starts when ventricular\n
the AV valve to open, allowing blood to flow\n
The atria contract to finish the filling phase\n