As the name sounds, cardiac muscle is located in the heart. It is also known as myocardium. The thick muscle of the heart contracts to pump blood out and then relax to let blood back in after it has circulated through the body.
All the types of muscle requires movement of actin against myosin to generate contraction. Cardiac and smooth muscle contraction are generated by internal pace maker cell. The contraction of skeletal muscle is stimulated by electrical impulses which is transmitted by the nerves. However, all skeletal and many of smooth muscle contractions are stimulated through a neurotransmitter known as acetycholine.