Osteon structural unit of compact bone Lamellae rings around the central canal

Osteon structural unit of compact bone lamellae rings

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Osteon: structural unit of compact bone Lamellae: rings around the central canal and site of lacunae Lacunae: cavities containing bone cells Canaliculi: tiny canals Yellow bone marrow stores fat located in bone shaft Trabeculae: branching plates in spongy bone Osteocyte: mature bone cell Osteoblast: bone forming cell Osteoclasts: bone destroying cells Bone remodeling is performed by both osteoblasts and osteoclasts Osteogenic cells have high mitotic activity, only cells that divide In embryos, there is primarily hyaline cartilage and fontanelles Osteogenesis: bone formation Ossification: cartilage replaced with bone 1. Endochondral ossification: development of clavicle, mandible, skull and face 2. Intramembranous ossification: ossified hyaline cartilage: limbs, vertebrae, hips Calcification: deposition of calcium ions into the bone tissue Bones grow in width (appositional growth) Repair of bone fracture Hematoma formed Fibrocartilage callus
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Callus replaced by bony callus Callus remodeled to form a permanent patch Exercise is very important for bone -> mineral recycling makes bones thicker and stronger Calcium Homeostasis/Bone Remodeling Parathyroid releases parathyroid hormone Thyroid gland releases calcitonin Thyroid gland releases thyroxin Pituitary Gland releases growth hormone and IGF-1 Requirements Calcitriol synthesis requires vitamin D3 Vitamin C Vitamin A Vitamin K and B12 Magnesium Estrogen Axial Skeleton is made up of skull, sternum and vertebrae Appendicular skeleton is everything else Major fontanels of infant skull 1. Anterior fontanel (soft spot) 2. Posterior fontanel 3. Sphenoidal fontanel 4. Mastoid fontanel Vertebral column is made up of 26 bones: 7 Cervical 12 Thoracic: rib articulation 5 Lumbar: support weight of torso 1 sacrum 1 coccyx Primary curvatures are present at birth: curves of thoracic and sacral Secondary curvatures develop after birth: curves of cervical and lumbar Female Pelvis Smoother and lighter
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  • Spring '14
  • AGRAWAL
  • hyaline cartilage, mature bone cell

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