Actin and Myosin

Definition

Actin and myosin are two types of protein involved in muscle contraction and movement. They interact with each other to cause muscles to contract or relax.

Related terms

Sarcomere: This is the basic unit of a muscle's contractile system, composed of actin and myosin filaments.

Muscle Fiber: A muscle cell that contains many myofibrils, which are made up of sarcomeres.

Sliding Filament Theory: This theory explains how muscles contract, with actin and myosin sliding past each other to shorten the length of a sarcomere.