histology of cardiac muscle

• Contractile proteins of cardiac muscle arranged into sarcomeres, fibrils and fibres (like striated muscle) BUT they are branched.
• Made up of short individual cells with INTERCALATED DISCS between them.

Intercalated discs

Highly folded, interlocking areas of the cell membrane (sarcolemma), consisting of areas of adhesion to hold cells together in sheet formation.

They also have areas for rapid ion transport from cell to cell to allow waves of depolarisation (contraction) and re-polarisation (relaxation).

• Between cells there are numerous capillaries
• Within cells there are many mitochondria (high metabolic rate for long periods when needed)
• Tissue is MYOGENIC, but nervous system will alter frequency and force of contractions to meet the body's needs.

MYOGENIC

will contract and relax rhythmically if its own accord.