====== Muscle cell ======

[[Muscle cell]]s 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 system via peristalsis.

Intermediate [[filament]]s (IFs) are [[cytoskeleton]] components found in the cells of many animal species.

They are composed of a family of related [[protein]]s sharing common structural and sequence features. Initially designated 'intermediate' because their average diameter (10 nm) is between those of narrower microfilaments ([[actin]]) and wider [[myosin]] filaments found in [[muscle]] [[cell]]s, the diameter of Intermediate filaments is now commonly compared to actin microfilaments (7 nm) and microtubules (25 nm).