Anat-Test-3 - SKELETAL SYSTEM 1 Skeletal System all bones...

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SKELETAL SYSTEM 1) Skeletal System- all bones of the body plus their articulations a) Bone tissue i) Components (1) Mature cells (osteocytes) (a) Begin as osteoblasts- make intercellular substance found  outside cells (b) Result- cells in lacunae surrounded by intercellular  substance now called osteocytes (2) Intercellular substance (a) Fibers- collagen only (b) Matrix- hard material outside the lacunae (i) Organic- osteoid, ossein; rich in glycoproteins and  proteoglycans (ii) Inorganic- hydroxapetite crystals (calcium phosphate and  calcium hydroxide); accumulate on fibers hardens matrix b) Structural types i) Spongy, cancellous, or trabecular (weak and easily broken) (1) Trabeculae- plates of flattened bone, linear and slightly curved (a) Few linear lamellae (layers of hard tissue-bony matrix) (b) Spaces filled with red bone marrow- site of production of RBC  and WBC platelets ii) Compact, cortical bone (strong) (1) Several lamellae present in concentric circles- makes compact  bone strong iii) Comparison of spongy and compact bone c) Microscopic structure of compact bone- osteon, Haversian System i) Haversian Canal (vertical)- space in center of osteon (1) Contains- blood vessels, lymphatic vessels, nerve fibers (2) Lining- endosteum (membranous structure) ii) Lamellae- layers of hardened bony matrix in concentric circles (1) Lacunae contain osteocytes (2) Lamellae alternate with layer of lacunae and osteocytes to end of  Haversian system (3) In center: havesian canal
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iii) Lacunae iv) Canaliculi- fine tubes (1)Cross lamellae and connect lacunae to each other (interconnect) (2)Canaliculi in first lamella open into Haverisan canal (3)Extracellular fluid (ECF) distributed to all lacunae by canaliculi (4)Function: provide nutrients and remove wastes from cells v) Volkman’s Canal (horizontal)- in compact bone (1)Run horizontally; connect Haversian systems (2)Lined by endosteum (3)Runs from outer surface to bone marrow cavity (4)Transmission of blood vessels, lymph vessels, and nerve fibers from outer surface to bone marrow cavity vi) Outer circumferential lamellae- located outer surface of long bone vii)Interstitial lamellae- fill in spaces between osteons viii) Intercircumferential lamellae- around edge of bone marrow cavity d) Classifications of Bones (based on shape) i) Long bones- length greater than width (1) Bones of extremities (humerus, ulna, radius, metacarpals, phalanges, femur, tibia, fibula, metatarsals, phalanges) ii) Short bones- length and width about the same (1)Carpals and tarsals except calcaneus iii) Flat bones- 2 parallel plates of compact bone separated by spongy bone (1)Many skull bones (lacrimal, zygomatic, nasal, frontal, parietal, occipital), scapula, sternum, ribs iv) Irregular bones (1)Sphenoid, ethmoid, temporal, vertebrae, mandible, maxilla, pelvic, sacrum, coccyc, calcaneus, hyoid bone
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Anat-Test-3 - SKELETAL SYSTEM 1 Skeletal System all bones...

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