HEART MUSCLES

HEART MUSCLE

I used to wonder how my heart is beating regularly without any effort on my part.  The thought that GOD is organizing the beating of my heart so regularly made a firm conviction.

Heart muscle is involuntary striated in the sense the contractions are involuntary. Heart wall consists of three layers. The outer layer is epicardium, the inner thick layer is myocardium and the inner layer is endocardium. Endocardium layer is very thick compared to other two layers.

Coordinated contraction of cardiac cells causes pumping of the

blood out of the atria and ventricles to the blood vessels of the left body systemic and right lungs pulmonary circulatory systems.

Heart muscle cells rely on available blood and electrical supply to deliver oxygen, nutrients and to remove waste material carbon dioxide. The coronary arteries fulfill this function.

The cross striations of cardiac muscle are formed by rotating segments of thick and thin protein filaments. The proteins are myosin and actin. Actin filaments are thin whereas myosin filaments are thick. The cardiac muscle cells are branchlike instead of linear.

The cardiac muscles are held together by T-tubles, something thread like bands. Compared to skeletal muscle cardiac muscles have T-tubles are bigger and wider.   T-tubles play a vital role in excitation-contraction coupling.

Cardio muscle cells are interconnected by microscopic disks. This arrangement enables passage of electrical impulses required for developing contraction.        Cardiac cells are regenerated periodically. A 50 year old man would have regenerated 45% of his total heart muscles.

Heart is working 24/7 throughout a year. Naturally the heart muscles have been made so strong by GOD.