Histology Cartilage/Bone

bear mechanical stress; development of long bones, support soft tissue; shock absorbing; sliding area for joints; ECM-collagen, GAG (hyaluronic acid), proteoglycans, glycoproteins; avascular; low meta activity; surrounded by perichondrium (dense CT) except articular (synovial fluid)

Type 2 collagen with proteoglycans (onto HAs); GAGs hydrate (shock absorb); territorial matrix is basophilic because sulfated from GAGs; prone to calcification; chondrocyte produce alkaline phosphatase

depends on hormonal balance (GH/somatotropin, thryoxin, testosterone-GAGs); slowed by cortisone, estradiol; appositional and interstitial

inner cellular layer-chondroblasts, swollen, secrete collagen and ECM; outer fibrous layer

1) interstitial- mitotic division, in early stages; in epiphyseal plate and articular cart 2) appositional- differentiation of perichondrial cells [IGF1 in liver in response to GH regulates epiphyseal chondrocytes]

ear, epiglottis, auditory tube; elastic fibers from chondrocytes; less suscept to degeneration; does not calcify (hyalin does); orecin is special stain

collage 1&3; btw tendon and bone; less matrix, irregular bundles of collagen, parallel lines of chondrocytes; versican proteoglycan

calcified matrix; vascular-bone marros; source of Ca, phosphate; ECM-hydroxyapatite crystals

in periosteum (mesenchymal); mitosis; specialization; line canals; form osteoblast and maybe osteoclast; bone-lining cells:OB and OC

cuboidal to columnar (flat-inactive); syn. collagen 1, G.S.; basophilic; alkaline phosphatase; liberates phosphate from organic phosphate by hydrolysis (calcification); osteoid-newly syn matrix (GAGs); osteocalcin binds Ca (so does sialoprotein)

multinucleated; resportion pits/Howships lacunae; from monocytes; ruffled border (not in osteopetrosis); tartrate resistant acid phosphatase (TRAP), collagenase; eosinophilic (mito); pit reg by H+; cathepsin K-degrade collagen,elastin,gelatin,depends on H+

calcintonin: inhibits resorp, rid of ruffled border of OC; PTH: stimulated resorp (and desposition of trabecular) of OC, increases blood Ca, decreases alkaline phosphatase in OB

inorganic salts (Ca, phosph-form hydroxyapatite crystals and CaPO4) and organic matrix (type 1 collagen and G.S.); glycoproteins-bind calcium, osteonectin; Vit K dependent-osteocalin; GF's and cytokines

osteopontin-Ca sequester; osteocalcin- bind Ca, marker of OB and bone formation

CT covering; outer fibrous layer of collagen (fibrocytes), inner cellular layer of osteoprogenitor cells

single layer of osteoprogenitor cells lining marrow (w/adipose); bone surface important because appositional growth only in bone

from osteoblast; form gap jnts btw them (canaliculi); maintain matrix; some resorp and form

AKA-immature, woven, nonlamellar; first to appear during formation; replaced by secondary; irregular collagen, reduced minerals, more osteocytes (per area but with random arrangement), more G.S.; present if broken bone

AKA-mature, lamellar; collagen arranged in lamellae around canal; Haversian system/osteon; cementing substance w/matrix and few collagen; spicules/trabeculae get nutrition by diffusion (no canals)

flat bones; within mesenchymal tissue; starting point is pri ossific center; diff into osteoblasts and then osteocytes; spicules fuse giving spongy structure then compact

in hyaline cartilage, first stage: hypertrophy (glycogen,VEGF,alkalinephosphatase) and deposition to form calcified cartilage; second: capillaries grow in and OBs form bone collar, primary cent of ossif forms

where periosteal vessels and osteoprogenitor cells grown in during endochondral ossif.

growth in length, scaffolding for construction of cancellous bone within metaphysis; larger in rickets, smaller in scurvey

matrix vesicles secreted by OB, accumulate Ca (mito.) and have alkaline phosphatase and pyrophosphatase; at rupture they will form hydroxyapatite cystals

epiphysis grows faster; diaphysis becomes larger with 2 diaphyseal funnels (metaphysic); wider from appositional growth; epiphysis closes at 20 so no long growth but widening can happen

formation of bone on periosteum side; resorption on internal surface

osteoclastic chase, chondrocytic run

diarthrosis; ligaments and capsule at ends; synovial layer is in folds, cells are 2-3 layers upon loose-dense irreg ct; epitheliod; secretory and phagocytic cells; no BL; produces mucin/synovial fluid; gap junctions; blood cap, adipose, calcium concretions

primary=in diaphysis, subperiosteal bone collar and medullary cavity forming; secondary=in epiphysis, radial growth, five zones (hypertrophy-glycogen, alkaline phosphatase)

Vit A-endochondral growth; Vit K- osteocalcin