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Anatomy of Cardiac Muscles

Updated on August 24, 2010

Cardiac muscles is a type of muscle found only in the walls of the heart and is responsible for pumping blood throughout the body - the function being transportation and the transportation vehicle being blood. The heart is approximately the size of your fist, is very strong and resistant to fatigue as it works constantly, day and night, throughout your life.

Although, cardiac muscle is just about completely dependant upon oxygen to function whereas skeletal muscle can function using stored glycogen as fuel. Cardiac muscle therefore can get damaged easily and death can occur whenever there is a lack of oxygen.

Striated, involuntary cardiac muscle
Striated, involuntary cardiac muscle

Cardiac muscles are one of three muscle types found in the body:

1. Skeletal muscle

Skeletal muscle controls the body's movement and is generally under conscious, or voluntary control

2. Smooth muscle

The internal organs, on the other hand, with the exception of the heart, are made of smooth muscle, which works without conscious effort.

3. Cardiac muscle

Cardiac muscle has a similarity to the smooth muscle in that it beats involuntary, without conscious effort from you.

The cardiac muscle is created from the same striated muscle fibers as skeletal muscles, yet the muscle tissue of the skeletal muscle is both structurally and functionally varied and segregated from each other.

Cardiac muscle also differs from both skeletal muscle and smooth muscle in that its cells branch and are joined to one another via intercalated disks. These intercalated disks allow for communication between the cardiomyocytes. Intercalated disks are described to have 3 different cell to cell junctions:

1. Adherens junctions

2. Desmosomes

3. Gap junctions

The myocardium is considered as one single functioning unit, the most muscular part of the heart and mainly responsible for its contractions.

Cardiac muscle differs from the other two muscle types in that contraction can occur even without an initial nervous input. The cells that produce the stimulation for contraction without nervous input are called the pacemaker cells. The pacemaker is only responsible for the beating of the heart, not the heart rate. This allows the heart to continue to function even if the nerves are severed, as in the case of a heart transplant.


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    • katyzzz profile image

      katyzzz 7 years ago from Sydney, Australia

      Nice and informative hub, Durbanite