What is the Difference Between Contractile Cell and Pacemaker Cell?

Contractile cells and pacemaker cells are two distinct types of cells in the heart that serve different functions:

Contractile cells:

• Involved in muscular contractions to pump blood.
• Contain organized sarcomeres, which contribute to the contractile force of the heart.
• Have a resting membrane potential, and their action potentials are triggered when neighboring cells depolarize, opening voltage-gated Na+ channels on the next cell.
• Comprise the bulk (99%) of the cells in the atria and ventricles of the heart.

Pacemaker cells:

• Set the rate of the heartbeat.
• Anatomically distinct from contractile cells, as they have no organized sarcomeres and do not contribute to the contractile force of the heart.
• Responsible for creating rhythmic impulses that set the pace for the heart.
• Found in specific regions such as the sinoatrial (SA) node and atrioventricular (AV) node.

The key difference between contractile cells and pacemaker cells is that contractile cells are involved in muscular contractions for pumping blood, while pacemaker cells are responsible for creating rhythmic impulses that set the pace for the heart.

Comparative Table: Contractile Cell vs Pacemaker Cell

Contractile cells and pacemaker cells are both involved in the functioning of the heart, but they have distinct roles and characteristics. Here is a table comparing the differences between the two:

Contractile cells are involved in the actual contraction of the heart muscle, pumping blood through the circulatory system. They contain organized sarcomeres, which are responsible for muscle contraction. Pacemaker cells, on the other hand, are responsible for setting the pace of the heartbeat by creating rhythmic impulses. They do not have organized sarcomeres and are not involved in muscular contractions.