Physiology 3120 Lecture Notes - Lecture 16: Pulmonary Vein, Aortic Valve, Heart Valve
11 Aug 2016
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Document Summary
Cardiac cycle consists of events that occur during one contraction-relaxation period (shown here are two systoles with one diastole) One ventricular diastole when ventricles relax heart is in diastole quite a long time. One ventricular systole when ventricles contract heart is in systole quite a short time. There is atrial diastole/systole as well but traditionally cardiac cycle goes by ventricular diastole/systole. Cycle begins with ap generated at sa node can see two p waves in ecg at the bottom. Ap then spreads through atrial muscle cells through av node and bundle of his down to ventricular muscle cells and causes the ventricles to contract. Keep in mind the sequence of events as go through cardiac cycle. Pressure changes in aorta shown by top dashed line in pressure graph keeps going up and down. Pressure changes in la shown by bottom dashed line in pressure graph is not going up and down as much as aorta.
