Chapter 8- Muscles, Bones and Movement

8.1 Bones, muscles and joints

The human skeleton has several functions- gives shape, gives support, protects softer organs, enables us to move (an attachment point for muscles) and bone marrow produces blood cells
Bones contain living cells which make hard bone when incorporating minerals (eg. calcium salts)
Ligaments are strong bands of slightly elastic connective tissue which hold bones together
Cartilage cover the ends of bones, smooth to reduce friction and a shock absorber
Synovial fluid reduces friction by lubricating the joint
Muscles are attached to bones with tough tendons.
Muscles work in antagonistic pairs. When one muscle (the flexor) contracts, the other (the extensor) must relax
A muscle is either contracted or relaxed, but most muscles have cells which are contracted to maintain the body posture. Muscle tone is the amount of tension

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Good posture means that bones are in the correct position, and so are the internal organs. Poor posture can lead to back pain
A slipped (or prolapsed) disc is when the cartilage between vertebrae bulges out and presses on a nerve, and causes pain
Physiotherapists assess and treat people with restricted movement, chiropractors (and osteopaths) use hands to manipulate joints and muscles
Sprains are damage to ligaments, usually due to overstretching and tearing fibres in sport. It may cause bones to dislocate
Fractures are damage to bones, due to accident or osteoporosis (a degenerative condition where to little bone is made or it is lost)
Strains are damage to muscles due to tearing and stretching
Tendons can become inflamed due to overuse, or ill-fitting trainers
Cartilage can be damaged suddenly or by wear and tear, osteoarthritis can be caused by cartilage damage
Keyhole surgery (where tiny incisions are made) is used by orthopaedic surgeons to repair damaged joints, as it aids speedy recovery, as it reduces damage to surrounding tissues

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