Cartilage and Ossification Flashcards Preview

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Flashcards in Cartilage and Ossification Deck (14):
1

Healthy cartilage mechanical properties

Flexible
Fluid flows under load to dissipate force
Permeable so stiff in compression and doesn't deform

2

Cartilage composition

Chondrocytes
Fibrous ECM (collagen type II, sometimes elastin and type I)
Ground substance (glycosaminoglycans + proteoglycans)

3

2 types of cartilage growth

interstitial - bone length grows through continuous cell division
appositional growth - new bone added to perichondrium under periosteum and grows from outside

4

Collagen types

Type I - bone, skin, tendons, ligaments
Type II - cartilage, intervertebral disks, vitreous humour
Type III - skin, blood vessels, reticular
Type IV - basal laminae

5

Permanent cartilage in body

Trachea, ear, articular

6

Cartilage joint types

Synovial - mobile
Symphysis - slight movement with fibrous tissue between cartilage (fibrocartilage)
Synchondrosis - negligent movement, ossifies more in elderly (hyaline cartilage)

7

Tidemark

border between mineralised and unmineralised cartilage, more mineralised with age

8

where does cartilage mineralisation occur

tidemark
endochondrial ossification
hyaline cartilage with age

9

processes of bone formation

endochondrial ossification (long bones, cartilage replaced by bone)
Intramembranous ossification (flat bones, osteoblasts differentiate from progenitors to directly form bone)

10

Stages of endochondrial ossification

reserve cartilage
proliferation
hypertrophy
calcification
erosion (by blood vessels/osteogenic cells)
ossification (bone formation on cartilage scaffold by osteoblasts)

11

Vitamin D deficiency

defective mineralisation
In children rickets - growth plate widens and fails to be mineralised
In adults osteomalacia - newly-formed bone matrix doesn't mineralise

12

Osteoarthritis

from trauma, abrasion of collagen and loss of PG aggregates
sometimes irregular mineralised tidemark causes more erosion

13

Rheumatoid arthritis

autoimmune inflammatory (TNF-alpha, IL-1), primarily affects synovium

14

ossification centres

primary in diaphysis
secondary in epiphysis which keeps articular cartilage at end
epiphyseal growth plate between the two which eventually ossifies and becomes bone