The Skeletal System
Part 1: The Skeleton
Five Functions
The skeletal system has 5 main functions.
1. To give shape and support
2. Allows you to move
3. Protects vital organs
4. Produces blood cells
5. Stores minerals
Three Parts
The skeletal system is made of 3 parts:
Bones
Strong living tissue – 206 in total
Cartilage
Tissue more flexible than bone
Ligaments
Tissue that holds bones in place
Bones
Bones are complex living structures.
Bone is one of the strongest tissues in the
human body – and one of the lightest!
Bones are made of 4 materials:
Compact Bone
Spongy Bone
Cartilage
Bone Marrow
Compact Bone
Compact Bone
Solid outer layer of bone
Hard and dense, but not
totally solid
Contains blood vessels
Constantly changing
Spongy Bone
Spongy Bone
Found at ends of bones
Honeycomb shaped – lots
of small spaces within it
Light but very strong
Houses the bone marrow
Cartilage
Cartilage
Covers the ends of bones
Smooth, slippery & flexible
Acts as a shock absorber
Reduces friction from bones
rubbing against each other
Bone Marrow
Bone Marrow
Soft connective tissue
Two types of marrow:
red and yellow
Red makes red blood cells
Yellow stores fat for energy
Bone Anatomy
Compact Bone
Spongy Bone
Cartilage
Marrow
Types of Bone
Long Bones
In your arms, legs
Types of Bone
Short Bones
Wrist or ankle bones
Types of Bone
Flat Bones
Skull, shoulder blades
Types of Bone
Irregular Bones
In your spine & ears
The Skeleton
The Skeleton
Any Questions?
The Skeletal System
Part 2: Joints
What is a Joint?
A joint is where two bones meet.
Joints allow bones to move in different ways.
There are 2 major types of joints:
Movable Joints
Immovable Joints
Allow a range
of movement
Allow little or
no movement
e.g. hip, shoulder
e.g. skull
Immovable Joint
Immovable Joint
Where two or more
bones fuse together
e.g. skull
Movable Joints
There are 4 types of movable joints.
Pivot
Hinge
Ball & Socket
Gliding
Pivot Joint
Pivot Joint
Where one bone rotates
around another
e.g. neck, lower arm
Hinge Joint
Hinge
Moves forward
and backward
e.g. knee, elbow
Ball and Socket Joint
Ball & Socket
Can freely move
one bone in a circle:
widest range of motion
e.g. shoulder, hip
Gliding Joint
Gliding
One bone can slide
over another
e.g. wrist, ankle
Ligaments
Bones must be held together at joints.
Ligaments are strong bands of rope-like
tissue that hold bones in place.
Ligaments connect
bone to bone.
They keep bones from
slipping out of joints.
Cartilage
Bones can rub against each other at joints.
Cartilage is a smooth, flexible tissue
that reduces friction between bones
Cartilage covers the
ends of bones at joints
It acts as a cushion
and keeps joints smooth
Tendons
Muscles move bones at joints.
Tendons are rope-like bands of tissue
that pull on bones at joints.
Tendons connect
muscle to bone.
Tendons allow you
to move your body
Tendons
Cartilage
Tendon
Ligament
Any Questions?