What is my?

My, also known as muscle, is a contractile tissue found in animals. Muscle cells contain protein filaments of actin and myosin that slide past one another, producing a contraction that changes both the length and the shape of the cell. Muscles function to produce force and motion. They are primarily responsible for maintaining and changing posture, locomotion, as well as movement of internal organs, such as the contraction of the heart and the movement of food through the digestive%20system via peristalsis.

Muscles are primarily powered by the oxidation of fats and carbohydrates, but anaerobic chemical reactions are also used, particularly by fast twitch fibers. Muscle contraction is often classified as either voluntary or involuntary. Voluntary muscle, such as that of skeletal muscle, is controlled consciously. Involuntary muscle, including smooth%20muscle and cardiac%20muscle, is controlled unconsciously by the autonomic nervous system.

Muscle strength depends on factors such as fiber types and neural efficiency, and can be improved through training. There are three major types of muscle: skeletal muscle, smooth muscle, and cardiac muscle.