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10 Cards in this Set
- Front
- Back
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What is endochondral ossification
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1 of 2 essential processes that is crucial during fetal development of the mammalian skelton
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The mnemonic for EO?
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Boys Can't Pee During Erections
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What are the five stages of Endochondral ossification?
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Bony Collar formation
Cavity Formation Periosteal bud Invasion Diaphysis elongation Epiphyseal elongation |
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What happens during the bony collar formation?
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Mesenchymal cells differentiate into chondrocytes
Chondrocytes produce hyaline cartilage In primary ossifactuon centre osteogenic cells become osteoblasts Osteoblasts lay down osteoid at the peripheries of the shaft |
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What happens during the Cavity formation?
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Chondrocytes undergo hypertrophy
Signak for hyaline cartilage to harden Area becomes calcified and impermeable to diffusion. Cells die and a cavity forms |
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What happens during periosteal bud invasion?
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Graverobbing arteries abnd nerves invvade via the nutrient foramen into chondrocyte space
This allows Osteoclasts and Osteoblasts to do their work. Osteoclasts eat up cartilage and osteod lays down new spongy osteoid |
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What happens during Diaphysis elongation?
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Now there are sufficient resources in the centre to elongate the bone and so cells hyperplase and interstitially grow
Formation of a medullary cavity |
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What happens during Epiphyseal elongation?
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A secondary ossifaction centre appears
Go through same process: Hypertrophy of chondrocytes Calcification of Cartrilage Apoptosis and cavity formation Periosteal bud invasion |
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What is the end result?
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That cartilage only remains at the ends of long bones and at the epiphyseal plate
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What are the zones at the epiphyseal plates?
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Zone of resting cartilage
Zone of proliferation Zone of hypertophy Zone of calcification Bone of diaphysis |
