Skeletal Muscle

• The most common muscle is the skeletal muscle. Skeletal muscle connects to the bone using tendons. It is controlled by the somatic nervous system, meaning its functions are voluntary. Movement begins in the brain, where electrical impulses are sent to nerves that innervate the muscle tissue. When an impulse is received by the nerve and transferred to muscle fibers, the skeletal muscle contracts, providing the ability to walk, talk and move.
  
  

Smooth Muscle

• Smooth muscle is controlled by the autonomous nervous system, which means its actions are involuntary. Smooth muscle lines the gastrointestinal tract in the esophagus, small intestines and the colon. After swallowing, smooth muscle pushes food down the esophagus and into the stomach. The stomach releases food into the small intestine, where food nutrients are absorbed and the waste products are moved through the intestines and excreted.
  
  

Heart Muscle

• The heart is also controlled by the autonomous nervous system. It is controlled automatically and involuntarily. Although the heart is a part of the cardiovascular system, its tissue is actually muscle. The nervous system innervates the heart and signals it to contract, pushing blood from the ventricles into the arteries that feed the body oxygen and nutrients.
  
  

Contraction

• The contraction of muscles occurs when the brain sends an electrical impulse to the nerve that innervates the muscle tissue. Between the nerve and the muscle is a space called the synapse. The synapse is the connection where the neurotransmitter, acetylcholine, carries the signal from the nerve to the muscle tissue.
  
  

Calcium

• Calcium is also a main ion in the production of contractions and muscular movement. When acetylcholine transfers the signal from the nerve to the muscle tissue, calcium is released into the cells. The release of calcium allows for the sliding action between muscle fibers, which contract and provide movement. A healthy diet with enriched calcium supplements can be important for proper muscle contraction.