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The Musculo-Skeletal
System
Why Both?
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This system includes both skeletal and muscular
systems because they need each other to
function properly
The Skeletal System
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The skeleton is important because:
1.
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5.
It supports our body
It stores minerals
It allows us to move
It protects our internal organs
It makes blood cells
What are bones?
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Bones are living tissue
Inside bones is a soft tissue called marrow
New blood cells made by the marrow inside
Contain nerve endings (sense pain)
Lightweight and strong
Types of Bones
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There are two types of bones: compact and
spongy
Compact Bone:
hard outer layer of bones
 gives bones their smooth, white, and solid
appearance
 accounts for 80% of the total bone mass of an adult
skeleton.
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Types of Bone
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Spongy Bone
Made up of compounds that make the bone
lightweight
 Allows room for blood vessels and marrow
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Groups of Bones
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Bones are divided into groups
Flat
 Long
 Short
 Irregular
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Groups of Bones
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Flat
The purpose of flat bones is to
protect important organs and to
provide a flat surface muscle
attachment.
 Include: the cranium (skull), scapula
(shoulder blade), sternum (breast
bone), pelvis, ribs and hip bone
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Types of Bones
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Long
The bone is longer than it is wide (that’s how it is
classified)
 Growth plates at the end that are covered with
cartilage
 Include: femur, tibia
and humerus
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Types of Bones
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Short
Bones that are as wide as they are long
 Provide stability and support
 Do not move a lot
 Carpals and Tarsals (bones in wrists and feet)
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Types of Bones
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Irregular
Have their own category because they do not have distinct
shape
 Include bones in your jaw and vertebrae (backbone)
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Cartilage
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Tough and flexible
Found in the nose, outer ear and joints
Prevents cushioning and stops bones from
rubbing together
Minerals added to cartilage makes bone
Tendons
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A tough band connective tissue that connects
muscle to bone
Can only exert a pulling force
When a muscle moves, the tendon pulls and
moves the bone
Ligaments
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Tissue that connects bones to other bones to
form a joint (like elastic bands)
Prevents bones from moving at a joint and are
important in preventing dislocation
Joints
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Are the points of our skeleton where two bones
meet
Every joint contains cartilage, tendons and
ligaments
Cartilage coats the ends of the bones
Ligaments attaches two bones together
Tendons attach muscles to the bones
Types of Joints
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There are 3 types of joints
Fixed – does not allow movement
 Partially Movable – allows a little movement
 Movable – allows complete movement
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Partially Movable Joints
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Allows a very little movement by the bones
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Ex. The joints between our vertebrae
Fixed Joints
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The bones are tightly locked together so no
movement occurs
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Ex. Joints found in the skull
Movable Joints
 Ball
and Socket – allows movement in
almost all directions.
 One rounded end of the bone fits into the
socket end of another bone
 Ex. Hips and shoulders
http://www.bbc.co.uk/science/humanbody/body/factfiles/joints/gliding_joint.shtm
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Movable Joints
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Hinge Joint – allows movement in only one direction
like a door
Ex. Elbows, knees fingers and toes
http://www.bbc.co.uk/science/humanbody/body/factfiles/joints/gliding_joint.shtml
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Pivot Joint – allows movement from side to side
A bone rests and rotates on one spot back and forth
Ex. Neck, elbow and knees (also hinge joints)
Movable Joints
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Gliding Joint – where several bones come
together like a puzzle and can slide past one
another
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Ex. Wrists and ankles
http://www.bbc.co.uk/science/humanbody/body/factfiles/joints/gliding_joint.shtm
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