MUSCULOSKELETAL SYSTEM
THE SKELETON
Your skeleton is your body’s frame, which has three main
functions:
1. Support for your soft tissues – without a skeleton,
your skin and organs would collapse like a jellyfish
2. Protection for your organs – This is the main role of
your axial skeleton (skull, vertebral column, ribs)
3. Allow movement – This is the main role of your
appendicular skeleton (shoulders, arms, legs)
THINK…
WHAT ARE EACH OF THE
STRUCTURES IN YOUR AXIAL
SKELETON PROTECTING?
BONES
• Bones need to be strong so they do not snap or crumble
• Compression squashes bones, tension stretches them
• Bones must be slightly elastic, so they can flex/twist a little
and then return to their original shape
BONE STRUCTURE
• Compact bone – the outer layer of bone, is dense and
heavy, and gives the bone strength
• Spongy bone – is light, and looks like honeycomb, filled
with bone marrow where red blood are made
Types of Joints
1. Fixed joint
Allows little movement:
Ex. joints of the bones in
your skull
2. Pivot Joint
One bone rotates around
another bone:
Ex. turning your head;
rotating your wrist
© 2014 Getting Nerdy, LLC
3. Ball-and-socket joint
The ball end of one bone
fits into a cuplike cavity
on another bone.
Ex: Shoulder or hip joint
4. Hinge joint
Back and forth
Ex: knee or elbow joint
© 2014 Getting Nerdy, LLC
5. Sliding joint
One part of a bone
slides over another
bone.
Ex: Bones of wrist or
ankle
© 2014 Getting Nerdy, LLC
MUSCLE:
an organ that can relax and contract, which
moves your body. There are two types:
Voluntary muscles: muscles you can control (bicep)
Involuntary muscles: muscles you cannot control
(heart)
© 2014 Getting Nerdy, LLC