1. The Skeletal System
Incredible Human Machine – Bare Bones

2. Your BONES Produce blood Protection Give shape. Help move
Provide chemical storage
Protection  CLICK
Shape  CLICK
Movement  CLICK

3. BONES are classified by shape
Look at the bones on your table. Classify them….
Long bones – longer than they are wide, usually they have a shaft with heads at both ends. They are composed of mostly compact bone. All bones of the limbs except the wrists and ankles, and patella are long bones
Short bones – generally cube shaped, composed mostly of spongy bone, bones of the wrists and ankles, and Sesamoid bones which form within tendons i.e. patella are short bones.
Flat bones – thin, flattened and usually curved, composed of two layers of compact bone with a layer of spongy bone in the middle, most bones of the skull, the ribs, and the sternum are flat bones
Irregular bones – if they don’t fit into the other categories then they are irregular bones. Mostly spongey Vertebra and hip bones

4. Bone Structure
Bones are composed of connective tissue, chemicals, and fats
Solid outer layer -compact bone
Composed of
Osteons
An inner layer of spongy bone
a honeycomb of
flat, needle-like
projections called
trabeculae.
Bones are organs. Thus, they’re composed of multiple tissue types.
Compact Bone consists of multiple cylindrical structural units known as osteons or haversian systems.
Imagine these osteons as weight-bearing pillars that are arranged parallel to one another along the long axis of a compact bone.
Spongy Bone is interconnecting rods or plates of bone. Like scaffolding.
Spaces filled with marrow.
Covered with endosteum.
Oriented along stress lines
Compare compact and spongy bone as viewed with the light microscope
Trabeculae: interconnecting rods or plates of bone. Like scaffolding.

5. Note the gross differences between the spongy bone and the compact bone.
How are spongy bone and compact bone different?
Descriptive words
What do you think is the purpose of compact bone?
Found in areas of strength like the shafts of long bones
What do you think is the purpose of spongy bone?
Found along lines of stress, it can transfer stress without breaking

6. BONES are grouped by location
Axial
skeleton
Appendicular
skeleton

7. Vertebral Column, Rib Cage
Axial
Skeleton
Skull,
Vertebral Column, Rib Cage
Vertebral column:
Regions: cervical, thoracic, lumbar, sacral, coccygeal
Intervertebral disks: cushion vertebrae; assist in movement, flexibility
Ribs:
Twelve pairs
Bottom two pair floating
Sternum: Breastbone:
Three bones fused

8. Shoulder Girdle, Pelvic Girdle,
Appendicular
Skeleton
Shoulder Girdle, Pelvic Girdle,
Arms & Legs
Pectoral girdle: shoulder:
Clavicle, scapulas
Pelvic girdles: hip:
Coxal bones, sacrum, pubic symphysis
Limbs:
Arms: humerus, radius, ulna, wrist and hand bones
Legs: femur, tibia, fibula, ankle and foot bones

9. Interesting facts
The longest bone in your body is the bone above your knee, the thighbone.
Your funny bone isn’t a bone at all.
When you were born, you had more than 300 bones. By the time you stop growing, you’ll have 206.
Your bones are living. They grow as you get older.