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Unformatted text preview: 1 The Skeletal The Skeletal System System The Skeletal System The Skeletal System Bones, joints and cartilage Functions s Support of the body s Protection of soft organs s Movement via attached skeletal muscles s Storage of minerals (mainly Ca ++ & P) s Site of blood cell formation (in bone marrow) The Skeletal System The Skeletal System s 206 bones in 2 divisions s Axial Skeleton (80 bones) s Skull (cranium + facial bone) s Trunk (vertebral column + thorax) s Appendicular Skeleton (126 bones) s Extremities + their attachments (pectoral & pelvic girdles) Classification of Bones based Classification of Bones based on Shape on Shape Classification of Bones based on Classification of Bones based on Shape Shape Long bones s Make up the majority of the extremities s Have a shaft with heads at both ends s Contain mostly compact bone s e.g. in femur (thigh), in humerus (arm) Short bones s Generally cube-shape s Contain mostly spongy bone s e.g. in carpals (wrist), in tarsals (ankle) Classification of Bones Classification of Bones Flat bones s Thin & flattened s Usually curved s Thin layers of compact bone around a layer of spongy bone s e.g. in the skull, ribs & sternum Irregular bones s Irregular shape s e.g. in the vertebrae & hip 2 Osseous Tissue Osseous Tissue s Compact bone s Dense, smooth & homogeneous s Found in the shaft of long bones s Spongy bone s More open spaces than compact bone s Small needle-like pieces of bone s Found at end of long bones and at the center of the other bones Osseous Tissue: Membranes Osseous Tissue: Membranes Periosteum: s Fibrous connective tissue membrane s Covers outside of bones (except the joints) s Perforating fibers secure it to underlying bone s Connects to tendons & ligaments s Anchors blood vessels & nerves s Inner cells contain osteoblasts Endosteum: s Lines the medullary canal s Contains cells which aid bone growth & repair Osseous Tissue: Bone Marrow Osseous Tissue: Bone Marrow Yellow marrow s In the central cavities of the long bone s Composed largely of fat Red marrow s In spongy bone (i.e. at the ends of long bones & center of other bones) s Manufactures RBCs & WBCs s Proportions vary by age & health s at birth, red marrow is present throughout the skeleton; by 20-25 years, red marrow conversion to yellow marrow is usually complete Microscopic Anatomy of Bone Microscopic Anatomy of Bone Osteon (Haversian System) s A unit of bone s Central canal + matrix rings Central (Haversian) canal s Opening in the center of an osteon s Carries blood vessels & nerves Perforating (Volkmans) canal s Perpendicular to the central canal s Carries blood vessels & nerves Microscopic Anatomy of Bone Microscopic Anatomy of Bone s Lacunae s Cavities containing osteocytes (mature bone cells) s Arranged in concentric rings (the lamellae) s Lamellae s Rings around the central canal s Sites of lacunae s Canaliculi s Tiny canals s Radiate from the central canal to lacunae s Form a transport system Microscopic Anatomy of Bone Microscopic Anatomy of Bone 3...
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This note was uploaded on 05/04/2008 for the course HP 320 taught by Professor Islam during the Spring '08 term at USC.
- Spring '08