Physiology 3120 Lecture Notes - Lecture 4: Aortic Valve, Heart Valve, Qrs Complex
20 Jan 2018
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The mechanical and electrical events during a single contraction at rest including: these values change during exercise or stress. Pressures changes in aorta, left atrium and left ventricle. Volume changes in left ventricle: left ventricle fills and empties as the heart contracts and relaxes. Ecg: p wave depolarization of atrial muscles, qrs complex depolarization of ventricular muscles, t wave repolarization of ventricular muscles. Phonocardiogram (heart sounds: there"re two heart sounds (lub and dub) and there"s a third heart sound that"s occasionally heard in young children but not generally heard. Opening and closing of valves (left av valve and aortic valve) Consists of a period of: ventricular diastole (when the ventricles are relaxing) lasting 0. 53s, ventricular systole (when the ventricles are contracting) lasting 0. 27s. There are 7 phases in one cardiac cycle: 1. Isovolumetric (ventricular) contraction: 3. (rapid) ejection period, 4.
