BIOS30344 Lecture Notes - Lecture 15: Wiggers Diagram, Acetylcholine, Heart Sounds

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7 Dec 2017
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T wave ventricular repolarization and whole-heart relaxation. These mechanisms occur just after the corresponding de/repolarizations. Passive filling into all areas of the heart 80% filling of ventricles. Atrial contraction systole last 20% atria to ventricles - ~135ml a. Qrs complex isovolumic ventricular contraction all valves are closed some tension, no muscle shortening insufficient pressure to open semilunar. Ejection full muscle shortening from apex to base opens semilunar valves into arteries a. Stroke volume is the difference between the end-diastolic volume and the end-systolic volume sits at an average of 70ml. Cardiac output = heart rate x stroke volume. ~70bpm under this control would be ~100bpm without this. Acetylcholine muscarinic receptors binding of an inhibitory g-protein that opens k+ channels (and closes na+ through camp inhibition) which leads to hyperpolarization and a decrease in hr. Sympathetic affects both nodes and the ventricular myocardium.