Download Skeletal System

Skeletal System
(Our Skeleton & Joints)
Function
• Protects
The skeleton protects delicate organs
-the skull protects the brain
-the vertebral column
protects the spinal cord
-the rib cage protects
the heart and lungs
Supports
• The body needs a framework
-the skeleton gives shape
to the body
(otherwise you would
be a blob on the floor)
-holds vital organs
in place
-provides a place for
the muscles to
attach to
Moves
Muscles act on bone
to cause movement
The skeleton is jointed
which allows a wide
range of movement
How do we move?
•
Joints help us move (where 2 or
more bones meet)
• There are 100 different joints in
the body- These can be put into
three different groups
Immovable joints- Found in the
skull
Slightly movable joints
-Limited movement found
in the Vertebral column
Freely Movable Joints
-Lots of movement i.e elbow.
Ball and socket joint (Type)
Name of ball and
socket joints
-Hip
-Shoulder
These joints can move
in all directions
Hinge Joint (Type)
Name of Hinge joints
-Knee
-Elbow
Allow movement in
one direction only
What makes us move?
• Muscles act on a
joint causing it to
move. The muscle
is attached to the
bone by tendons,
muscles contract
pulling on the
tendon causing it to
pull on a bone.
Why do muscles work in
pairs?
•
•
Muscles can only contract( pull on
a bone) they cannot push.
To bend your elbow the bicep
muscle Contracts (pulls on the
tendon attached to the lower arm
bone)
this brings the arm towards the
shoulder as the elbow joint bends.
To straighten the arm the triceps
muscle pulls on the tendon
attached to the lower limb to
straighten the arm.
The muscle that works is called the
(agonist) the other muscle relaxes at
the same time (antagonist)
Parts of a joint
(acts as a lubricant)
(Acts as a shock
absorber and
prevents two
surfaces from
rubbing together)
(found at the end of
muscles and is
attached to the
bone)
Ligaments
Ligaments connect bones
to other bones to form a
joint (They do not
connect muscles to
bones; that is the
function of tendons.)
ligaments are strong
fibrous bands that hold
the joint together and
prevent certain
movements