KINESIOL 1AA3 Lecture Notes - Lecture 3: Pulmonary Artery, Aortic Valve, Aorta
26 Apr 2017
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Cardiac output + regulation of stroke volume +regulation of heart rate. The cardiac cycle: consists of contraction (systole) and relaxation (diastole) of both atria, rapidly followed by systole and diastole of both ventricles, electrical events, mechanical events, pressure changes, heart sounds, volume changes. Atrial systole: atria contracting, ventricles are relaxed: depolarization of sa node causes atrial depolarization (p wave, atrial depolarization causes atrial systole. As atria contact, they exert pressure on blood and force blood through open av valves into ventricles: atrial systole contributes a final 25 ml of blood to volume inside ventricles. End of atrial systole is end of ventricular diastole. This blood volume is called the end-diastolic volume (edv: qrs complex in ecg marks onset of ventricular depolarization. Ventricular systole: ventricles contracting, atria relaxed: ventricular depolarization causes ventricular systole. Pressure rises in ventricles and pushes blood against av valves, closing them. 0. 05 seconds, both semilunar and av valves are closed isovolumetric contraction.
