01:830:305 Lecture Notes - Lecture 17: Myocyte, Cardiac Output, Afterload
30 Oct 2014
School
Department
Course
Professor
Document Summary
Action potentials recorded in sinoatrial (slow myocyte) and purkinje fibe r (fast myocy te) Note: these are only 3 phases of the action potential in the slow myocyte, but five phases in the fast myocyte. True pacemaker cells do not have a resting membrane potential. Phase 0 in the fast response cell na dependent (upstroke potential), slow ca dependent (na not involved) Maximum diastolic depolarization one is 30mv less than the other. Volume in the left ventricle at the end of the systole is reduced by about 50% Intake and output phase each of these can be further subdivided. Relating all the events in the cardiac cycle simultaneously. Pay attention to 2 vertical grey scale bars: one to left marks the period of isovolumetric contraction, one to right marks the period of isovolumetric relaxation. Isovolumetric metric (measure of) volume, iso the same = the volume is not changing. When systole ends and diastole begins, what valves are open, etc.
