NURS 364 Lecture Notes - Lecture 1: Pulmonary Valve, Left Coronary Artery, Right Coronary Artery
14 Dec 2017
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Alteration in cardiovascular systems: nurs 364 - pathophysiology. Automaticity--- sa node starts impulse travels through atrium to av node then goes into ventricles spreads to tissue around two ventricles and spreads around heart. Ventricles have some automaticity also but at a much slower rate. Diastole---- heart is filling muscle relaxed and blood comes into body from vena cava filling heart or from pulmn art to left heart. Herat fills up then all valves shut muscle contracts- builds pressure then the atrial valve and pulmonic valve open and the blood all leaves. Av valves open & ventricular filling occurs. Coronary perfusion occurs at this phase of the cardiac cycle. Diastolic time is inversely proportional to heart rate. Amount of blood found in the ventricles at the end of diastole measure of volume important because of another factor:force of contraction is related to preload better preload= better contraction. The greater the stretch (within physiologic limit) the greater strength of contraction.
