B5 Bones and Joints

BONES AND CARTILAGE

A skeleton supports, protects and allows movement. Vertebrates all have an internal skeleton, invertebrates, however, have external skeleton. An internal skeleton easily grows with the body, is more flexible, easy to attach muscles and provides the body more support.

As bones grow they are able to repair themselves. Long bows are hollow which makes them lighter and movements more efficient. The hole in the bone is filled with bone marrow.

Bones begin as cartilage though when you grow it is replaced by bone. This is die to blood vessels depositing calcium and phosphorus in the cartilage (ossification).

Bones are very strong but with a knock they can be broken (fractured). Elderly people tend to break bones more often as they can suffer from osteoporosis which is where calcium is lost from the bones which causes them to be more brittle. When a bone is broken it shouldn't be moved this is due to it may damage nearby tissue.

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  • Created by: Kitty
  • Created on: 23-03-13 14:29

BONES AND CARTILAGE

BONES AND CARTILAGE

A skeleton supports, protects and allows movement. Vertebrates all have an internal skeleton, invertebrates, however, have external skeleton. An internal skeleton easily grows with the body, is more flexible, easy to attach muscles and provides the body more support.

As bones grow they are able to repair themselves. Long bones are hollow which makes them lighter and movements more efficient. The hole in the bone is filled with bone marrow.

Bones begin as cartilage though when you grow it is replaced by bone. This is due to blood vessels depositing calcium and phosphorus in the cartilage (ossification).

Bones are very strong but with a knock they can be broken (fractured). Elderly people tend to break bones more often as they can suffer from osteoporosis which is where calcium is lost from the bones which causes them to be more brittle. When a bone is broken it shouldn't be moved this is due to it may damage nearby tissue.

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JOINTS AND MUSCLES

JOINTS AND MUSCLES

Synovial joints are held together by ligaments which have a high tensile strength. The bones are covered in cartilage to prevent the bones from rubbing together.The synivial membrane releases synovial fluid in lubricate the joints. 

Ball and socket joints (for example the hip or shoulder) can rotate and move in all directions. Hinge joings (for example the knee or elbow) can move backwards and forwards.

Tendons connect the muscles and bones. Muscles move the bones at a joint by contracting. Muscles come in antagonistic pairs, when one muscle contracts the joint moves in one direction, if the other joint contracts it moves int the opposite direction.

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