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18 Cards in this Set
- Front
- Back
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What is a Haversian system?
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Concentric circles of bone lamellae arranged around a channel of blood vessels and nerves
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Where does increase in length occur in bone?
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Epiphyseal growth plate
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Where does increase in width occur in bone?
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Periosteum
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What are the 5 zones of the epiphyseal growth plate?
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Resting zone
Proliferation zone Maturation zone Hypertrophy zone Degenerative zone Osteogenic zone |
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Describe the resting zone
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Hyaline cartilage containing chondrocytes
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Describe the proliferation zone
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Actively dividing chondrocytes, forming columns of cells, strong basophilic matrix with proteoglycans
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Describe the maturation zone
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Chondrocytes cease to divide
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Describe the hypertrophy zone
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Cells swell and become vacuolated and matrix calcifies.
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Describe the degenerative zone
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Chondrocytes start to die and leave spaces around calcified cartilage spicules for osteoprogenitor cells to invade
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Describe the osteogenic zone
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Osteoprogenitor cells divide into osteoblasts on top of calcified cartilage and bone formation occurs. Woven bone stains eosinophilic
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When is lamellar bone laid down from woven bone?
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After stress:
Compressive strain Increased weight Muscle pull |
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What are the 3 stages of fracture repair?
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Inflammation
Repair Remodelling |
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What occurs in the inflammation stage?
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Haematoma is formed. Phagocytic cells come in and osteoclasts clear clot and necrotic tissue. Neovascularisation occurs and granulation tissue is laid down.
First few days after fracture |
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What occurs in the repair stage?
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Migration of mesenchymal cells to fracture as well as chondrocytes and osteoblasts. Hyaline cartilage and woven bone forms provisional callus. Hyaline cartilage undergoes endochondral ossification = bony union/fracture repair.
Weeks to months following fracture |
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What occurs in the remodelling stage?
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In response to normal use, woven bone is replaced with lamellar bone
Months to years after fracture |
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What are the functions of sesamoid bones?
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Reduces friction of tendon
Changes direction of tendon pull Prevents tendon wear/injury |
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What are splanchnic bones and give an example
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Bones formed in soft tissue organs remote from the rest of skeleton.
e.g. os penis |
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What are pneumatic bones?
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Bones that contain hollow cells full of air
(confined to skull in mammals) |
