Cardiac muscle


The cardiac muscle is created from the same striated muscle fibers that skeletal muscles are created, yet the muscle tissue of the skeletal muscle is both structurally and functionally varied and segregated from each other. The cardiac muscles are much shorter, they branch out, and they are interconnected via by intercalated disks.

These intercalated disks are vital in the communication process. Within the cardiac fibers, any originating action potential can be expressed through the myocardium and run through the intercalated disks to send signals to the muscular heart fibers.


The myocardium is in fact considered one single functioning unit as physiological union of these cells act in complete cohesion with each other. This configuration is known as syncytium. This action contributes to the differences between the cardiac muscles and the skeletal muscles as the skeletal muscle rely on more direct communication to control each individual movement.

The cardiac muscles act in complete cohesion, which basically means either all the fibers work at the same time and create a heart beat or none of the fibers work at all and there is no heart beat. Additionally, the cardiac muscle commit to action potentials automatically, rather than the direct involvement of the neurons required by the skeletal muscles.


Cardiac Muscle
Image: Cardiac Muscle

The term used to describe the automatic regular action of the heart beat is known as myogenic action. This term is deemed to any muscle action independent of immediate neuron involvement.

There is a group of cells within the heart known as the pacemaker. The pacemaker refers to the cell mass that stimulates the heart’s actions. The pacemaker is only responsible for the actual beating of the heart, not the heart rate. The heart rate is stimulated and regulated via autonomic innervation. Spontaneous depolarization can not be handled by the pacemaker.
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