<unk>  is a type of involuntary striated muscle found in the walls of the myocardium.<unk>  is one of three major types of muscle, the others being skeletal and smooth muscle.
Coordinated contractions of<unk>  cells during systole propel blood out of the atria and ventricles to the blood vessels of the systemic and pulmonary circulatory systems.
The inherent contractile activity of the heart is extensively regulated by the autonomic nervous system.
Cardiac muscle
Skeletal muscle
Nervous tissue
Lymphatic tissues
Heart
Endocardium
Ventricle 
Papillary muscle