What are four characteristics of pacemaker cells?

Answer 1

These cells look just like regular heart cells. But some create rhythmical impulses and they directly control the heart rate.

The sinoatrial node (SA node) is a group of these cells positioned on the wall of the right atrium. Because the sinoatrial node is responsible for the rest of the heart's electrical activity, it is sometimes called the primary pacemaker.

Further down into the heart at a junction between the artium and ventricles is the AV node which is called the secondary pacemaker.

The last part of electrical conducting system of the heart is the Bundle of His which include left and right branches of this bundle, and the Purkinje fibers. These will also produce a spontaneous action potential at a rate of 30-40 beats per minute, if the SA and AV node both do not function.

Answer 2

1. Automaticity: Pacemaker cells have the ability to spontaneously generate action potentials.
2. Rhythmicity: They have a regular, intrinsic firing rate that sets the pace for the heart.
3. Conductivity: Pacemaker cells can conduct electrical impulses to stimulate neighboring cardiac cells.
4. Excitability: They are sensitive to changes in ion concentrations and respond by firing action potentials.