The Heart's Conducting System
Click on the + symbols to reveal more information about the heart's conducting system.
Click on the + symbols to reveal more information about the heart's conducting system.
The Sinoatrial node lies in the right atrium and generates its own electrical potentials (normally at over 100bpm). However at rest the vagus nerve, slows this down to around 60 bpm. The medulla oblongata can also increase the rate of action potentials being released with the signal travelling through T1-4 to reach the heart.
The Bundle of His fibres takes the electrical signal from the AV node and makes it travel down the interventricular septum. The His bundle splits into a left and right bundle branch either of which could become blocked causing a conduction delay.
The AV node receives signals from the SA node and delays them to allow the atria to contract first before the ventricles. In the absence of an SA node signal the AV node will depolarise spontaneously at 40-60bpm (escape rhythm).
The purkinje fibres allow electrical signals to be dispersed amongst the myocardial cells.
