Term
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Definition
Synthesize osteoid (unmineralized matrix)
Align into sheaths on surface of bone, connected by gap junctions
Suppress deposition in response to PTH |
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Term
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Definition
Are located in Lacunae surrounded by bone and are derived from osteoblasts (that have surrounded themselves with bone).
connect to eachother and haversian canal by canaliculi |
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Term
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Definition
| haversian canal with circumferential layers of bone |
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Term
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Definition
| Ability of osteocyte to both reabsorb and produce osteoid. |
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Term
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Definition
squamous layer of cells on all bone surfaces not covered by osteoblasts.
The quiescent form of osteoblasts |
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Term
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Definition
Bipotential mesenchyme stem cells that can become osteoblasts or chondroblasts.
Reside either in the marrow cavity, within the haversian canal, or the inner cellular layer of the periosteum |
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Term
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Definition
Large multinucleated cell for bone resorption (derived from monocytes)
Polarized |
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Term
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Definition
| subosteoclastic compartment that osteoclast sits atop of |
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Term
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Definition
Side of osteoclast that faces the howships lacunae that has many basal enfoldings.
Many H+, Cl- channels and ATPases |
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Term
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Definition
on either side of the ruffled border
Rich in actin and integrins for linkage to bone surface |
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Term
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Definition
| Opposite of ruffled border that has Cl/HCO3 exchanger to maintain intracellular ionic balance |
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Term
| Parathyroid hormone (PTH) |
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Definition
Secreted in response to low blood Ca++.
Inhibits osteoblasts and stimulates them to secrete osteoclast stimulating factor |
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Term
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Definition
| Ligand produced by osteoblasts to stimulate preosteoclasts to differentiate into osteoclasts |
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Term
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Definition
Secreted by parfilicullar cells (of thyroid) in response to high blood Ca++
Directly inhibits osteoclasts |
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Term
| Intramembranous bone formation |
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Definition
| formed directly from condensation of well vascularized mesenchyme without the pre-existing cartilage model |
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Term
| Endochondral Bone formation |
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Definition
| bone formed in relation to a cartilage model |
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Term
| Woven (Primary) vs. Lamellar (secondary) |
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Definition
Woven Bone is:
more cellular
more ground substance and less collagen
grows and reabsorbs more rapidly
mineralizes more rapidly but less completely |
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Term
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Definition
secreted by hypertrophied chondrocytes (in endochondral bone formation) to increase the amount of phosphate Ca++ crystals
enventually burst to give up crystals |
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Term
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Definition
Secreted by hypertrophied chondrocyte.
Binds to existing type II collagen (of cartilage) and then binds the mineral cyrstals
forms a temporary mineralization for osteoblasts to situate on |
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Term
| primary ossification center |
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Definition
| Forms in the diaphysis of an endochondral bone and is where bone matrix is initially layed down on scaffolding |
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Term
| Secondary ossification center |
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Definition
| Forms postnatally in the ends of long bones and projections of vertebrae. |
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Term
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Definition
| layer of hyaline cartilage between the primary and secondary centers of ossification |
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Term
| Zones of the epiphyseal plate |
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Definition
Zone of Resting Cartilage
Zone of proliferation
Zone of hypertrophy and maturation
Zone of calcification and degeneration
Zone of reabsorbtion and ossification |
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Term
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Definition
| Alteration of size/shape of bone by the simultaneous bone formation and reabsorption on different surfaces |
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Term
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Definition
| The replacement of old/woven/structurally inferior bone by a sequence of resorption and production of new lamellar bone |
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Term
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Definition
first immature woven bone laid down at fracture, it is weaker but compensates by being lager in diameter.
Eventually replaced by lamellar bone. |
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