Cardiac muscles are the muscles that are only found in the heart region.
1) They are striated but involuntary (i.e. not under the control of our will). They facilitate involuntary movements with the help of special cells called pacemaker cells. So, they have intermediate function.
2) Structurally, these muscles form an intermediate type of both striped and unstriped muscles. They are cylindrical, branched and uninucleated.
3) These muscles consist of cylindrical fibre interconnected by oblique bridges forming contractile network.
4) There is presence of intercalated discs in the fiber, which allows the fiber to interlock for greater strength during contraction. Intercalated discs also permit rapid spread of contractile stimuli from one cell to another.
5) There is great abundance of mitochondria related with enormous metabolic demand.
6) There is supply of central nervous system and automatic nervous system.
7) They contract rhythmatically but do not get fatigued.
8) They are rich in lipid content.