HTHSCI 1H06 Lecture Notes - Lecture 3: Interatrial Septum, Interventricular Septum, Purkinje Fibers

• School: McMaster University
• Department: Health Sciences
• Course: HTHSCI 1H06
• Professor: Peter Helli

Document Summary

Cardiovascular physiology: components of cardiac conduction system (& their roles, sa node, av node, bundle of his, l & r bundle branch, purkinje fibers. Sa node: part of a group of fibers (auto-rhythmic fibers) that naturally depolarize fires (cid:1005)(cid:1004)(cid:1004) (cid:271)p(cid:373) parasy(cid:373)patheti(cid:272) syste(cid:373) slows it dow(cid:374) to a(cid:271)out 7(cid:1004)- 75 bpm: av node: located in the interatrial septum, self-excitable, fires on its own (40-60 bpm), bundle of his: av bundle, only point where the signal will move from atria to ventricles, interventricular septum. Left and right bundle branches: purki(cid:374)je fi(cid:271)ers: i(cid:374)flue(cid:374)(cid:272)ed (cid:271)y ele(cid:272)tri(cid:272)al dis(cid:272)harge fro(cid:373) si(cid:374)oatrial (cid:374)ode (cid:272)arry out contraction impulse from left and right bundle branch to myocardium of ventricles, cardiomyocytes (syncytium, intercalated disks) Syncytium: cardiac muscle works together to stimulate contraction. Sodium flowing in voltage gated channels: rapid, brings rmp to +20, plateau period due to calcium inflow, calcium is essential to myosin for contraction.