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Skeleton & Muscular
System
Junior Certificate
What are the Functions of the
Skeletal System??
To Support the body
Without bones you would collapse into a
jelly-like mass
 Skeleton gives your body shape and holds
all the parts of your body upright.
 Therefore bones form the structure of your
body

Functions of the Skeletal System
To Allow movement
To Protect delicate organs
Skull
protects brain
Spinal cord is protected by the backbone
Heart, lungs and liver are protected by ribs
Can you estimate how
many bones we have?
Adult bones = 206
Children > 206
Bone has two parts
A living part on
the
inside which has:
 Cells
 Blood vessels
 Nerves
A non living part
on the outside
made of calcium
This part is rock
hard and it is
made by the
living part which
releases the
calcium
Compact bone is
on the outside
and is hard
Spongy bone is
inside this and
has lots of holes
like a sponge
Bone marrow is
on the very
inside and
makes blood
cells
Therefore Bone is
composed of a
A
hard, non living part (Compact
bone )
 And a flexible living part (Spongy
bone)
 The living part has a network of
blood vessels which carries
minerals and other nutrients in and
out of your bones.
Would you believe!!!
 Bones
are broken down and
rebuilt throughout life
 There are two kind of bone
cells that work together to
make the bone grow;
 Osteoblasts (bone builders)
and Osteoclasts (Bone
destroyer)
The bones of the body
Skull
Ribs
Collar bone
Breast bone
Shoulder blade
Vertebrae (backbone)
Humerus (upper arm)
Radius and ulna (Lower
arm)
Pelvis (hip)
Femur (thigh)
Tibia and fibula (lower leg)
All vertebrates have a
spine
Its made up of bones called
vertebrae.
Each vertebrae has a disc of
cartilage between them
The cartilage;
 Acts as a Shock absorber
 Allow limited movement
 Stop bones rubbing off
each other
A slipped disc
Joints!!!what are they??
Joints are places where two bones join
together
Can you name any kind of
joint in our body?
Do not allow bones
Fused
to move
Appear as if they
are stitched
together
Therefore fused
joints don’t allow
bones to move
e.g skull
Synovial Joints
Allow bones to move
1.
Ball and
socket
1.
Hinge
elbow
Allows movement in several
directions – e.g hip &
shoulder
Allows movement in one
plane only – knee, elbow,
jaw, knuckles
Structure of Synovial joint
It Contains a lubricating fluid
called Synovial fluid
Synovial fluid acts as a shock
absorber – allowing bones to
move and prevent friction
Ligaments – tough, elastic
fibres hold the bones together
Cartilage – covers bones and
stops bones from knocking
against each other – in order
to prevent chipping little
pieces of bone off each other
What do you think connects a
muscle to a bone?
Tendons


anchor muscle to
bone
When the muscle
contracts the joint
and tendons bend and the bone moves
What do you think joins bones to
each other?
Ligaments


strong band of tissue
that join bone to bone
hold two bones
together without
stretching
So how do we move??
Muscle contract –
pulls on the bone and
gives movement
Muscles can only
Contract (gets
shorter)
Therefore needs
another muscle to pull
the bone in opposite
direction
How does her arm move?
Antagonistic muscles
Is a pair of muscles which pull in opposite
directions
Example; Biceps and
triceps muscles of the
upper arms
When the biceps
contract, the arm is
raised
When the triceps
contracts the arm is
lowered
Fun Games
Bones can
you name
them
Bone
Quiz
Skeleton
Shakedown