Skeletal muscle

Skeletal muscle (also known as striated muscle) acts under voluntary contraction, is attached to bones and functions to carry out movement and help maintain posture. It is made up of actin and myosin proteins which make up the sacromere, as well as the regulatory proteins troponin and tropomyosin. Contraction of a skeletal muscle is stimulated by release of calcium ions form the sacroplasmic reticulum which bind to troponin and cause a conformational change. This change causes tropomyosin to be released which causes the myosin-binding site on the actin molecule to become visible and so myosin can bind to the actin, causing a cross-bridge to form and the muscle to contract.

The myofibrils within the skeletal muscle create a banding pattern of light and dark striations due to the thickness of the myofibrils changing as the muscle contracts.