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Skeletal System
Types of Bones

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Pre-Quiz
Types of Skeletons
Joints
Skeletal Functions
Types of Bones
Structure of Long Bones
Microscopic Structure
Skeletal Development
Axial Skeleton
Appendicular Skeleton
Interactive Skeleton
Diseases, Disorders and Fractures
Links
Post-Quiz

There are two basic types of bone tissue found in the skeletal system, along with cartilage.
 
Spongy Bone - Texture results from needlelike threads of bone (trabeculae) surrounded by a network of open spaces.  Spongy bone is found in epiphysis (ends) of long bones where the spaces contain red bone marrow responsible for reb blood cell formation. 
 
Compact Bone - Has a basic structural unit called osteon, composed of coencentric lamella, lacunae containing osteocytes and canaliculi, and covered with periosteum.

osteon.gif

Cartilage - Structural unit is chondrocyte, contains a gel-like matric and lacks blood vessels.

chondrocyte.gif

Individual bones are classified by their basic shape and placed into four basic groups:
 
 
Long -  longer than they are wide, act as levers for the muscular system and bear the
    weight of the body  (Click for structure)
    Ex:  femur, tibia, fibula
 
 
Short -  basically shaped like a cube, allow skill and ease in movement
    Ex: carpals and tarsals

long_short_bones.jpg

Flat - have broad surfaces for basic function: to protect organs
     Ex: skull, ribs, pelvic bones, shoulder blades
 
 
Irregular - doesn't fit into the other three categories
     Ex: vertebrae

irregular_flat_bones.jpg