Muscles and the skeleton

Bones
1. The human skeleton is made up of 206 bones.
2. Most bones are hollow and contain marrow.
  1. Marrow helps bones to be light and strong
3. Bones are a mixture of living tissue and non-living material
  1. Living tissues contain cells and collagen fibres which allow bones to be flexible
  2. The non-living part is made of mineral salts like calcium phosphate which hardens the bone.
Functions of the skeleton
1. Support
  1. 1. They provide support allowing the body to stand upright
2. Protection
  1. 2. They protect most of the main organs including the brain heart and lungs
3. Movement
  1. 3. They allow movement with the help of muscles
4. Blood production
  1. 4. Blood is produced in the marrow of bones
Joints
1. A place where two bones meet is called a joint. There are three types of joints:
  1. 1. Fixed joints- where there is no movement although bones meet
  2. 2. Hinge joints- where bones move only in One Direction
  3. 3. Ball and socket joints- where bones can swivel and move in any direction
  4. Parts of a joint
    1. Cartilage: A tough smooth substance that covers bone surfaces at movable joints.
    2. Ligaments: A smooth, flexible material that holds bones together at movable joints
    3. Tendons: Attach muscles to bone and transmits the pull of muscle to bone
    4. Synovial fluid: lubricates the joint and reduces friction
Muscles
1. Muscles move bones at joints
2. Muscles cannot push and so joints need pairs of muscles (antagonistic pairs) to pull in the opposite direction
  1. One muscle contracts (gets shorter and fatter) to pull a bone.
    1. At the same time
      1. The other muscle in the pair relaxes (gets longer and thinner
3. Exercise strengthens bones and muscles. Too much exercise can damage muscles and joints.

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Muscles and the skeleton

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	Creado por Amelie Mataskova hace más de 8 años