Download Control of the Heart Rate (students)

Control of the Heart Rate
Electrical impulse flow chart below.
SA node AtriaAV nodeAV bundle (Purkinje fibers)Ventricles

SA node is the pacemaker of the heart located in the upper right handside
of the right atrium.

It’s like a ‘spark plug’ that fires electrical signals through the upper
chamber of the heart causing them to contract and push the blood down
into the lower chambers.

That impulse then reaches a structure at the bottom of the right atrium
called the atrio-ventricular node (AV node).

The AV node acts as a bridge pathway (electrical relay station) between
the upper chambers and lower chambers.

The impulse then travels down to the apex of the heart via the ‘Purkinje
fibres’ where ventricular contraction begins.

The impulse then travels upwards, spreading rapidly through both of the
ventricle walls activating them and causing them to contract and pump
the blood out to the body.

The main arteries now close, and while the ventricles relax, the cycle has
already started again.