HLSC 3P90 Lecture Notes - Lecture 1: Cardiac Cycle, Capillary, Sinoatrial Node
12 Sep 2017
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Document Summary
Cardiac anatomy: located in the mediastinum (middle of thorax, tope heart - upper right portion of the chest, below the second rib and right of sternum, apex - lies just above diaphragm on the left. Function of pericardium: reduces friction during heart beats, keeps the heart secure in mediastinum, protects heart from bacteria. Atria: top of the heart, thin walled, low pressure chambers, separated by interatrial septum, function as large reservoirs conduits of blood for their respective ventricles, right atrium, receives deoxy blood from the venus system. Consists of specialized cells that initiate each heartbeat and electrically coordinate contraction of the chambers: sa node - small mass of cells located in wall of right atrium, located to right of superior vena cava entrance. Isovolumic contraction: onset of ventricular contraction coincides with peak of r wave on ecg, semilunar + av valves are closed, earliest rise in ventricular pressure.
