Summary Grade 9: NS: Revision

Musculoskeletal system
 The skeleton protects, provides support and enables movement in the body.
Bones, however cannot move on their own and require the assistance of muscles.
Muscles enable movement throughout the body. They attach to the outside of
bones and work together to allow movement.
Components:
 Muscles
 Cartilage
 Ligaments
 Bones
 Tendons
Bones attach to other bones by means of ligaments. These are flexible and prevent
dislocation of bones. Muscles are attached to bones by means of tendons. Tendons
are tough and inelastic. The joints enable flexibility. Joints are formed where two or
more bones meet in the body- joined by ligaments. The places where bones meet are
covered in cartilage- this prevents friction where bone meet and movement takes
place.
Main processes:
 Contraction and relaxation of muscles
 Movement
 Locomotion
The main processes of the musculoskeletal system include the contraction and
relaxation of muscles, movement and locomotion. Our muscles are made up of cells
known as muscle fibres. These fibres have the ability to relax and contract via signals
from the brain. Musculoskeletal muscles work in pairs: one muscle contracts, whilst
the other relaxes. They work by pulling on the bone. An example of muscles working
together would be the biceps and triceps the ability to move from one place to
another is locomotion. The movement of our muscles and skeleton allow us the
ability to walk, run and jump.
Health issues:
 Rickets
 Osteoporosis
 Arthritis