Functions of the skeleton
- Protection - the cranium and ribs protect the brain and vital organs in the chest.
- Shape - gives shape to the body and makes you tall or short.
- Support - holds your vital organs in place when playing sport. The vertebral column holds the body upright.
- Movement - muscle are attached to bones, which are jointed. When the muscles contract the bones move.
- Blood production - red blood cells (to carry oxygen) and white blood cells (to protect against infection) are produced in the bone marrow of some bones.
Names of bones
Cranium (skull) Scapula (shoulder blade)
Vertebral Column (spine) Humerus (upper arm)
Rib cage Radius (outside forearm)
Sternum (breast bone) Ulna (inside forearm)
Pelvic Girdle Carpals (wrist)
Femur (thigh bone) Metacarpals (hand)
Patella (knee cap) Tarsals (ankle)
Tibia (shin bone) Metatarsals (foot)
Fibula (behind shin bone) Phalanges (fingers and toes)
The Vertebral Column (image)
Types of vertebrae
- Supports head and neck
- Top vertebra (atlas) allows head to nod
- Second vertebra (axis) allows head to rotate
- Ribs are attatched, which make a protective cage
- Allows some movement
- Allows a large range of movement
- Prone to injury
- The bones are fused togeter
- Make a strong base and transmit force from legs to upper body
- Fused vertebrae, no special use
- Act as shock absorbers between vertebrae
Synovial joint image
Cartilage reduces friction. Acts as a shock absorber.
Synovial fluid lubricates the joint.
Synovial membrane produces synovial fluid.
Tendon joins muscle to bone enabling movement.
Ligament joins bone to bone, stabilising the joint.
Abduction - moving the limb away from the mid-line
Adduction - moving the limb toward the mid-line
Flexion - bending the limb at a joint
Extension - straightening a limb out at a joint
Rotation - moving the limb around a fixed point
- the bones of embryos are mainly made of cartillage
- the process of ossification uses calcium to create bone
- bones gradually become hard and strong
- with age, bones lose their density and strength. When severe this is called osteoporosis
- eating food containing calcium and exercising helps bones to develop and stay strong
Types of bone
1. Long e.g femur, humerus - for movement with strength and speed
2. Short e.g carpals, tarsals - for shock absorption, spreading the load
3. Flat e.g cranium - protection of vital organs, attachment of muscles to help movement
4. Irregular e.g vertebrae, face - provide shape, protection
The composition of a Long Bone
Hyaline cartilage - covers the ends of the bones, stops them rubbing together and absorbs shock.
Epiphysis - the ‘head’ of the bone.
Cancellous bone - spongy bone that stores the red bone marrow; where blood cells are made.
Epiphyseal plate – the area where bones grow in length.
Diaphysis - the shaft.
Compact bone – hard, dense bone. It gives strength to the hollow part of the bone.
Periosteum – a protective layer where there is no hyaline cartilage. Ligaments and tendons attach to the periosteum.
Medullary cavity/marrow cavity - contains the yellow bone marrow; where white blood cells are made.
Types of joints
Hinge e.g elbow, knee - flexion and extension
Pivot e.g axis and atlas (top of neck) - rotation of one bone around another
Ball and socket e.g hip, shoulder - flexion, abduction, adduction, rotation
Saddle e.g thumb - flexion, extension, adduction, abduction, circumduction
Condyloid e.g wrist joints - flexion, extension, adduction, abduction, circumduction
Gliding e.g intercarpel joints - gliding movements
Types of joints (image)