THE MUSCULO-SKELETAL SYSTEM

The body is supported by a systems of harder tissues - cartilage and bone. Cartilage is a rubbery substance found on the ends of bones, in the ear lobes and nose. Bone contains hard insoluble calcium salts.

Many bones have spaces inside them filled with marrow. The marrow makes bone and is involved in the immune system.

The hard materials of bone are constantly being laid down and replaced. This means that bones can be repaired if broken

Parts of the body that can move are often centred around joints between the bones

ie. Pivot Joint - rotation movement eg. base of neck
Hinge Joint - flexing movement eg. elbow, knee
Ball & Socket Joint - movement in all directions eg. hip and shoulder

There are also joints between bones which do not allow movement -> immovable joints

Joints are held together by ligaments

The parts of the body on each side of the joint are moved by muscles -> organs which can contract

Muscles are attached to bones by tendons

Muscles are often paired to cause movement

eg. biceps -> contract to flex elbow (triceps relax)
triceps -> contract to straighten elbow (biceps relax)

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