Answer:
Skeletal muscles operate under voluntary control – this means that we ask them to move, and they do. Involuntary muscles (smooth muscle) work whether we consciously ask them to or not – for example, the muscles that line the digestive system.
Skeletal muscles are made up of muscle fibres, bundled together. Each fibre can contract or relax on demand. All fibres contract together to shorten a muscle. The command to contract or relax is given by the brain and relayed to the muscle by nerves.
Mainly, muscles move the skeleton by working in opposite pairs. For instance, if you bend your elbow, your biceps (muscles on the front of the upper arm) contract and the triceps (muscles on the back of the upper arm) relax. It works the other way if you straighten your arm – the triceps contract while the biceps relax.
Explanation:
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