Contraction: Muscle cells get shorter (contract) in response to nerve impulses Structure Your skeletal muscles are made up of bunches of elongated, rod-shaped cells called muscle fibres.

Firm muscles. Your muscles are in a constant state of partial contraction, which keeps them firm, healthy and ready for action at all times. This is called muscle tone and it's the only aspect of ...

Expressions: Contraction of your facial muscles changes your facial expression Expressive muscles You contract the muscles beneath your skin as a form of non-verbal communication.