Video - Action potentials in pacemaker cells

Action potentials are voltage changes that propagate along the surface of cells. In the heart, they are generated by specialized cell structures called pacemaker cells, which use them to control the rhythmic contraction of muscles.

In cardiac pacemaker cells, action potentials occur when specialized channels in the cell membrane open and allow ions to flow into or out of the cell. This change in electric charge makes the cell more positive on the inside, which attracts more ions from neighboring cells and triggers a chain reaction that propagates the action potential along the heart muscle. This eventually leads to the contraction of the heart and pumps blood around our bodies.