The functions of cardiac muscle are:
1. Contraction: Cardiac muscle cells contract and relax in a coordinated fashion to pump blood out of the heart and into the blood vessels.
2. Electrical conduction: Cardiac muscle cells are able to conduct electrical impulses, which stimulate them to contract.
3. Automaticity: Cardiac muscle cells have the ability to generate electrical impulses spontaneously, which allows the heart to beat without external stimulation.
4. Refractoriness: Cardiac muscle cells are refractory, or resistant to stimulation, after they have contracted. This prevents the heart from contracting too rapidly.
Cardiac muscle is a specialized type of muscle tissue that is found only in the heart. It is essential for the functioning of the heart and the circulation of blood throughout the body.