Download Skeletal System - Holy Family Regional School

The Skeletal System
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What is the job of the frame/walls of
a building?
Why do you think we have bones?
What do you think would happen if
we didn’t have bones?
When a baby is born, not all of the
bones in their skull have fused together
so they have soft spots.
Bone Formation
Cartilage breaks down over time to get
replaced by bone
– Osteoblasts are bone-forming cells that
deposit calcium and phosphorus to make
bones.
At birth, your skeleton is 300 +
separate bones - as you age they fuse.
As adults, you only have 206.
What is the Skeletal
System?
• The framework of
bones and other
tissues that
supports the body
Bones
• The BONES are the organs of the body.
• Made up of tissues.
Tissue
Description
Compact Bone
The hard, dense outer layer
of bone
Spongy Bone
Hard, but has many “holes”
in it
Marrow
Soft tissue with the spongy
bone, makes blood cells
Compact Bone
Compact bone is directly under the
periosteum - it is living tissue!
Provides strength to bones
Made of calcium phosphate deposits
Contains bone cells and blood vessels
Spongy Bone
Spongy bone is near the ends of longer
bones.
Contains lots of small spaces to make
bones lighter.
Cavities in spongy bone are filled with
marrow. Marrow can be yellow and be
made of fat cells, or red and produce red
blood cells.
Cartilage
Cartilage is a thick tissue layer
covering the ends of bones.
Cartilage is slippery and thick to be a
shock absorber and to reduce friction
when bones rub together.
Bones and Cartilage
Functions of the Skeletal
System
•
•
•
•
•
Shape and Support
Movement
Protection
Production
Storage
Shape and Support
Skeleton determines
shape of your body just
like the frame
determines the shape of
a building
Movement
• Bones form joints,
which is a place
where two bones
come together
• Joints allow bones to
move in different
ways
Joints
A joint is any place where two or
more bones come together.
Cartilage always holds healthy bones
apart.
Ligaments hold healthy bones in
place. A ligament is a thick band of
tissue.
You have immovable and movable joints.
Immovable joints don’t allow movement
(duh). Ex: Bones in the skull.
Movable joints DO allow movement.
There are different types: pivot, ball
and socket, hinge, and gliding. They
allow different types of movement.
Protection
Skull protects your brain
Rib cage protects heart, lungs,
and other organs in the center
of your body
Production
Bones produce blood
cells. The long bones
in your arms and legs
can be thought of as
factories that make
certain blood cells.
Storage
• Bones store minerals until body
needs them
– These minerals include calcium and
phosphorus, which are in many foods
we eat
Care of the System