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The locomotor system is also known as the musculoskeletal system. It is made up of the skeleton, the skeletal muscles, tendons, ligaments, joints, cartilage and other connective tissue.

These parts work together to allow movement

The brain controls the movements of the body, using information from: the muscles themselves, called ‘muscle sense’ or kinaesthesia. Bones are a form of connective tissue reinforced with calcium and bone cells. Bones have a softer centre, called marrow, where blood cells are made.

The three main functions of the skeleton are:

  • support – the body is supported
  • shaped by the skeleton – for example upright posture would be impossible without a spine protection – our internal organs are protected by our skeleton
  • such as the brain inside the skull
  • the heart
  • lungs inside the ribcage movement – most skeletal muscles are attached to bones in opposite working groups
  • like the biceps
  • triceps muscles of the upper arm

The skeleton also stores minerals (such as calcium) and lipids (fats), and produces blood cells in the 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. Generally, 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. In some joints, like the shoulder joint, many different muscles are attached.

This allows even greater freedom of movement

Some common problems of the locomotor system include:

  • occurs when bones lose minerals such as calcium more quickly than the body can replace them. They become less dense
  • lose strength
  • break more easily inflammatory disease. About locomotor the eyes the ears
  • such as inflammation osteoporosis bone fractures – caused by falls or accidents back pain
  • neck pain overuse or mechanical injuries such as tendonitis
  • muscle or ligament strains