Question

The term autorhythmicity refers to the heartʹs ability to ________.

A) conduct action potentials along the conduction pathway
B) generate its own contractile cycle
C) originate its contraction neurogenically
D) act as a functional syncytium
E) intrinsically modify its contractility

Answer 1

Autorhythmicity is the ability of the heart's pacemaker cells to independently initiate an electrical impulse that controls the heart's beating cycle, without external nervous or endocrine influences.

Step-by-step explanation:

The term autorhythmicity refers to the unique ability of cardiac muscle to initiate its own electrical impulse independently of nervous or endocrine control. This intrinsic property ensures that the heart can initiate and sustain its beating or contraction cycle at a constant pace. The pacemaker cells, or self-excitable cells, are central to this process, being able to depolarize to the threshold and fire action potentials at set intervals to maintain a steady heart rate. These cells are part of the sinoatrial (SA) node and are responsible for the autonomous beating of the heart. The electrical impulse generated by these cells then propagates via gap junctions to other conductive and contractile cells throughout the heart, allowing for coordinated contractions of cardiac muscle which constitutes the pumping action necessary to circulate blood effectively.