Functions of the Skeletal System:
*Rigid framework *Supports the body *Gives the body shape *Protects vital organs *Assists in movement *Manufactures blood cells *Stores calcium and other minerals
Axial skeletal system
Head, thorax, trunk (80 Bones)
Appendicular skeletal system
Upper and lower extremities (126 bones)
Material of bones
1/3 organic material -Living -Gives bone elasticity
2/3 inorganic material -Nonliving -Hardness, strength
Compact bone
Hard, dense outer layer
Cancellous bone
*Porous and sponge-like inside *Thin areas/ lattcework
Epiphysis
End of long bone becomes dense as we age (Osseous in adults) Wider than the shaft of long bones
Epiphyseal plate
Growing bone Cartilaginous Where growth occurs
Pressure Epiphysis
Ends of long bones Receives pressure from opposing bones
Traction epiphysis
Tendons attach to bones Subject to traction force not involved in joint formation
Diaphysis
Main shaft of long bone characterized by its compactness and strength.
Medullary canal
Center of diaphysis, hollow, decreases weight. Allows for passage of nutrient arteries
Endosteum
Membrane that lines the medullary canal
Osteoclasts
Contained in endosteum, responsible for bone resorption.
Periosteum
Fibrous membrane covering bone, except articular surfaces.
Long bone characteristics
Length greater than width Largest in body Most of appendicular skeleton Tube shaped with diaphysis/epiphysis
Short Bone characteristics
More equal in height, length, and width Cube shape Large of articular surface Articulate with more than one bone
Flat bone
Broad surface, not thick Curved surface
Irregular bones
Mixed shapes Specific function
Sesamoid bone characteristics
Where tendons crass ends of long bones Within tendons Change angle of tendons attachment, increase force production
Fracture of the bone
Broken bone Can be caused by direct force, inderect force, pathology
Osteoporosis
Loss of normal bone density or mass May weaken to point of fracture
Studied by 38 People