L11 Cartil And Bone Flashcards
LO2: classif 3 maj types, desc struc diffs.
- hyaline- ma conts pg’s, hyaluronic as, T2 Coll. Hyal pg aggregs bound to fine Coll ma fibs.
- elastic- ma like hyaline, with lot elastic fibres and elast lamellae. Stain and see microsc.
- fibrocartil- lot T1 Coll fibres-thick bundles. Ma of hyaline. Fewer cells.
LO3: rel anat distrib of each type to diff funcs.
HYALINE:
-chondroc cells only, in isogenous grps Sep as elab ECM. Feral precurs bones-endochondral ossif. Some remains at artic surfs of long bones and epiphyseal plate until stop grow.
-LOC: artic surfs bone, costal cartil, nose, larynx, C trachea, compl ring prim bronchi, crescents//plates sec and tert bronchi.
-perichondrium covs margin of hyaline cartilage. Conts lot elong fibrob like cells round up and dev to chondrobl then chondroc. Fibrob sec ma compons. Res in apposit growth from periph-widening. Is dense CT. chondrocs deeper mito tic div and form isogenous grps which deposit ma= interstit growth. Cells Sep as lay ma. Dense CT to perichondrium to growing cartil (apposit) to v sulfated territ ma (stains dark arnd chondrocs) and lighter interstit ma. No perich at artic surfs but contrib said to dev jnt caps. Dense CT edge.
-cartil ECM v hydrated and transient movem water in ma=resil to press- elec, mech, chem sigs direc synthet activ of chondrocs-how much ECM and where. Epiphysis spongy cancellous bone. Hyal cartil forms growth pl. meta and diaphysis.
ELASTIC:
-lot elastic fibres in ECM=elast and resil. Not calcify or ossify with age.
-LOC: pinna ear, ext acoustic meatus, epiglottis, eustacian tube btw mid ear and nasal pharynx for press eq. HEAD AND NECK.
Pinna- epid to dermis to fibrocollag tiss to elast cartil to adip to musc.
Epig- dark stain elastic fibres, perich.
FIBROCARTIL:
-conts chondrocs and fibrob. Comb dense reg CT and hyal cartil. Cells often in rows. NO perich surr. resil to shock abs and resis shearing force.
-LOC- intervert disc. Artic disc of sternoclavicular and temporomandibular jnts. Pubic symphysis. Knee menisci btw tib and femur.
Intervert- T2 Coll. Chondroc in rows or isog grp. Rel few elong fibrob.
Fibrocartil at some enthesis- att tend to bone. Tend dense reg T1. Fibrocartil lot T1 binds in with T2. Mineralised fibrocartil periph to bone.
Menisci T1 bundles, hyal pg aggregs, chondroc irreg distrib and less abund.
LO4: desc char feats and funcs diff types bone.
-bone rigid and living. Lot B+LV and nerves.
Funcs- supp, protec, reserv inorganic subst eg Ca, P. Osteo cells and Coll. Calcified ma.
-2 types-
Cancellous- porous v vasc. Netw cols/plates=strng and light. BM in sp. comm at epiphyses.
Compact/cortical- outer lay. 80% skel mass.
LO5: desc compons bone- cells and EC.
LO6: micro struc of compact and spongy bone.
-compact- outer tough fib periosteum. Thin cellul endosteum lines marrow cav. Osteon= Haversian canal and concentric lamellae. Interstit lamellae btw. Outer circumf lamellae. Volkmanns canal link haversian. Canals cont B+LV and nerves.
-immat bone- rand arr osteocytes.
Mat- osteocytes in concentric lamellae. Resorption canals paral osteon long axis. Osteoclasts remod, bore hole, lay down new osteon. Decalcif mat bone- lost oseoc. Osteon remod leaves interstit and concentric, resorp canals bored and new concent laid diff course. Osteons br and termin, often longit, same plane as bone. Unstained cortic bone- if not de calcified can grind down to thin lay. Be aware of osteon cut in diff planes. Canaliculi- tiny connec tunnels from oseoc carry protoplasm if thread, connec haversian, gas/nutr/waste btw lays. Connec by gap juncs.
-spongy struc of trabec- osteoc in irreg interstit lamellae. NO canals. Osteoblasts along trabec edge. Osteoclasts on surf too. =remod. Adip and haemopoietic cells in cavs.
LO1: desc composit cartil- cells and EC compons.
-cartil- a vasc tiss consis of chondrocytes in semisolid ECM. Chondrocytes prod and maint ECM. In lacunae. Cartil supps some soft tiss and slid surf in movab jnts. Most pre natal bones der as cartil.
Lot GAGs: T2 Coll in ma= ready diff nutr/gas/waste btw chondrocs and BV surr cartil (eg in perichondrium).
ECM solid, pliable, resil to rep press, shock abs. Lot hyaluronic as in ECM assists resil.
Surf flat cells- apposit growth-chondroblasts which form chondrocytes. Pg struc in cartil GS- pg monoc=core joined 100 GAG hyaluronic as molecs=Lin aggregs with lot pg. interwove with Coll. T2 Coll not thick bundles, stays thin fibrils. GAG neg attr H2O.
LO7: expl how bone is living tiss undergo remod and rep.
- growing bone spicule- osteoc in bone. Osteoblasts surr by new osteoid (blue hydroapatite) it has deposited=osteocyte. Big osteoclasts in spicule resort bone and low in res dep.
- bone remod- cut bone=boring tunnel by osteoclasts, rel H+ and lysis enzs. Osteoclasts at big end of cone in cut zone, osteoblasts furth back lay new concent lamella in closing zone, BV and loose CT in cone. Growth reversal lines sides of cone. Const occ in resp to stress.
- bone composit- 65% min (Ca hydroxyapatite crystal) v hard. 23% T1 Coll. 10% water. 2% non Coll prots.
LO8: desc cellul proc in bone rep foll frac-
-resis frac as tensile and comp strength. Also lamellae slip slight over each other. Bone break=bleed brok BV in canals=haematoma btw brok ends, brok nerves=pain.
-haematoma format- blood clot where granulat tiss arises. BV in bone adn periosteum break. Bone cells at frac edge die as no blood supply. Swell and inflamm, phagoc cells and osteoclasts rem dead/dam tiss, Mac ent rem clot.
-fibrocartillagenous calus- replaces pro callus of gran tiss. Bony trabec dev in fibrocartil callus. V early esp yng.
New BV infilt haematoma. Pro callus of gran tiss rich in capill and fibrob devs. Fibrob= T1 Coll span break. Others diff to chondrobl atts sleeve hyaline cartil. So ext bulge fibrocartil ma splints bone. More cent osteoblasts form peri and endosteum (and multi potent BM cells) invade frac site. =spongy/trabec bone.
-bony callus format- endoch and intramem ossif=bony callus of spongy bone. 1 wk new trabec in fibrocartil callus. Trabec dev as FC callus forms hard bony callus of spong bone. Ultim endoch ossif repl all cartil with cancellous bone but intramem ossif also pros new spongy bone. Cartil calcif and repl by new bone spicules. Can start 2d post frac in yng. Bony callus format contin 2 mnth til v firm Union.
-remod- cancel bone repl by cartil as soon as forms. Sev months. Mater bulge from outs and inw to medull cav rem by oseoclasts=patent shaft orig shape if good alignment.
SEE PHOTOMIC
-bone banks- if frac loss frags, bony Union and callus imposs. Banks for graft since 70s. Frags frozen. Autograft most SUCC. Homografts diff hum poss rejec. Heterog diff sp, calf bone loses antigenic its withe refrig.
