HTHSCI 1H06 Lecture Notes - Lecture 3: Interventricular Septum, Interatrial Septum, Purkinje Fibers
17 Jan 2019
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1h06b lecture 3- cardiac physiology: components of cardiac conduction system (& their roles) There are auto rhythmic fibers that are self-excitable, these make up the conduction system. Electrical stimulation before there is a physical response (depolarization before contraction) Fibrous skeleton of the heart acts as an insulator and is located around the valves. This helps to separate the atria from the ventricles also for electrical stimulation: sa node, av node, bundle of his, l & r bundle branch, purkinje. Sa node (sinoatrial): known as the pacemaker of the heart. It sets a natural pace at about 100 beats per minute. However, our average heart rate is about 70-75 beats per minute. Sa node depolarizes continuously, it will reach a threshold and stimulate the action potential to go through the conduction system. The action potential will then propagate to the av node which sits around the floor of the right atrium, around the interatrial septum.
