nn nn
Questions and Answers n n
bone
Ans-
organnmadenupnofnseveralndifferentntissuesnworkingntogethern(bonentiss
ue,ncartilage,ndensenconnectiventissue,nepithelium,nadiposentissue,nnervousntissu
e)
skeletalnsystem
Ans- entirenframeworknofnbonesnandntheirncartilages
basicnfunctionsnofnskeletalnsystem
Ans-
supportn[softntissues,nattachmentnofntendons]n
protectn[importantninternalnorgansnfromninjury]nassist
anceninnmovement
,mineralnhomeostasisn[storagenandnrelease]nblood
n cellnproductionn[rednbonenmarrow]ntriglyceriden
storagen[yellownbonenmarrow]
longnbone
Ans- hasngreaternlengthnthannwidth
diaphysis
Ans- isnthenbone'snshaftnornbody—
thenlong,ncylindrical,nmainnportionnofnthenbone
epiphyses
Ans- thenproximalnandndistalnendsnofnthenbone
metaphyses
Ans- thenregionsnbetweennthendiaphysisnandnthenepi-
n physes.nInnangrowingnbone,neachnmetaphysisncontainsnannepiphysealn(growth)nplat
e,nanlayernofnhyalinencartilagenthatnallowsnthendiaphysisnofnthenbonentongrowninnlen
gth
,epiphysealnline
Ans-
thencartilageninnthenepiphysealnplatenisnreplacednbynbone;nthenresultingnb
onynstructurenisnknownnasnthen
articularncartilage
Ans-
thinnlayernofnhyalinencartilagencoveringnthenpartnofnthenepiphysisnwherent
henbonenformsnannarticulationn(njoint)nwithnanothernbone.nArticularncartilagenred
ucesnfrictionnandnabsorbsnshocknatnfreelynmovablenjoints.
periosteum
Ans-
toughnconnectiventissuensheathnandnitsnassociatednbloodnsupplynthatnsurro
undsnthenbonensurfacenwherevernitnisnnotncoverednbynarticularncartilage.nItnisncomp
osednofnannouternfibrousnlayernofndensenirregularnconnectiventissuenandnanninnernos
teogenicnlayernthatnconsistsnofncells
medullaryncavityn(akanmarrowncavity)
, Ans-
hollow,ncylindricalnspacenwithinnthendiaphysisnthatncontainsnfattynyellownbo
nenmarrownandnnumerousnbloodnvesselsninnadults.nThisncavitynminimizesnthenweightn
ofnthenbonenbynreducingnthendensenbonynmaterialnwherenitnisnleastnneeded
osteoprogenitorncells
Ans-
unspecializednbonenstemncellsnderivednfromnmesenchyme,nthentissuenfromnw
hichnalmostnallnconnectiventissuesnarenformed.nTheynarenthenonlynbonencellsntonunde
rgoncellndivision;nthenresultingncellsndevelopnintonosteoblasts.
Osteoprogenitorncellsnarenfoundnalongntheninnernportionnofnthenperiosteum,ninnth
enendosteum,nandninnthencanalsnwithinnbonenthatncontainnbloodnvessels
osteoblasts
Ans-n bone-
buildingncells.nTheynsynthesizenandnsecretencollagennfibersnandnothernorganicn
componentsnneededntonbuildnthenextracellularnmatrixnofnbonentissue,nandnthe
yninitiatencalcification
osteocytes