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Discover fascinating facts about the skeletal system! Learn about bone terminology, the different parts of the skeleton, functions of bones, and the classification of bones by shape.
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The Skeletal System NO BONES ABOUT IT! Did you know? The adult skeleton has 206 bones
Terminology: Oste “bone” Art “joint” -blast “germ” or embryonic (creating/producing) -clast “broken” (destroying/break down) -cyte “cell” Peri- “around” Dia- “between or across” Epi- “upon” Hemat- “blood”
The Skeletal System Parts of the skeletal system • Bones (skeleton) • Joints (flexibility) • Cartilages (cushion) • Ligaments (connect bone to bone)
Functions of Bones • Support the body (internal framework) • Protect soft organs (vertebrae) • L • Allow movement due to attached skeletal muscles • Store minerals and fats (fats, calcium, phosphorus) • Hematopoiesis (Blood cell formation)
Two subdivisions of the skeleton 1. Axial skeleton (skull, ribs, spine) 2. Appendicular skeleton (pectoral girdle, pelvic girdle, bones of limbs)
Head • Long bones Have a shaft with heads at both ends • Typically longer than they are wide • Contain mostly compact bone • Examples: • Femur (longest bone in the body) Shaft Head Figure 5.1a
Anatomy of a Long Bone • Diaphysis • Compact bone • Protected by periosteum (membrane) • Epiphysis • Ends of the bone • Thin layer of compact bone • But mainly spongy bone in the middle • Protected by articular cartilage
Anatomy of a Long Bone • Medullary cavity • Cavity inside of the diaphysis • Contains yellow marrow (mostly adipose) in adults • Contains red marrow (for blood cell formation) in infants
2. Short bones • Generally cube-shape • Contain mostly spongy bone Example: • Carpals • Tarsals Figure 5.1b
3. Flat bones • Thin, flattened, and usually curved • Two thin layers of compact bone inside • Layer of spongy bone inside Example: • Skull • Ribs • Sternum
4. Irregular bones • Irregular shape • Do not fit into other bone classification categories • Example: • Vertebrae • Hip bones
5. Sesmoid bones • Develop in some tendons where there is considerable friction, tension, and physical stress • Only one found in all normal human skeletons • Example: • Patella