histology of bone by dr.danish :d

8/18/2019 Histology of Bone by dr.Danish :D

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Histology of

bonelecture 1&2DR KHADIJA IQBAL

PROF!!OR A"A#O$%


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A 2 yers ol' boy (it)

s)ort stture Presenting complaint:

1. Short Stature

2. Bowing of legs

3. Deformity of chest

History of presenting complaints:

A mother has brought her son 2 years ol who has shortstature for his age. He was eli!ere in hospital withelaye cry an history of strior. He also has swollen "nees

which are bent inwars.

Physical #$amination:

A baby girl with absent upper limb% the forearm is e$tremelysmall an eforme an it appears as though the han isirectly connecte to the upper arm.


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Structure and Location


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Gross observation shows


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Compact vs. Spongy BoneCo

mpact vs. Spongy Bone

Irregular, thin plates

= trabeculae Dense and solid


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Presence of compact &spongy

bone


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Bone


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In young growing bones and in older bones after

trauma, an inner cellular (osteogenic layer of the

periosteum is found deep to

!eriosteum

the fibrous layer.


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Bun'les of *eriostel collgen+bers


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"he spindle#shaped osteoprogenitor cells of this highly

vasculari$ed layer can differentiate into osteoblasts

that produce new bone.

!eriosteum


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%ndosteum # consists ofa fine reticular

connective tissue

containing

osteoprogenitor cellswhich may be

transformed

into osteoblasts.

Bone


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%ndosteum

&ining of the

bone surface

facing the

marrow andalso of

trabeculae


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%ndosteum

%nters

perforating

('olman

canals


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%ndosteum

Continues to

cover central

canals

endosteum


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Composition of bone

cells

fibers

Groundsubstance


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Histology of Bone #issue Four ty*es of cells re *resent in bone tissue

Osteogenic cells

,n'ergo cell 'i-ision .ste/ cells0 t)e resulting cells 'e-elo*into osteoblsts

Osteoblsts

Bonebuil'ing cells !ynt)esi3e e4trcellulr /tri4 of bone tissue

Osteocytes

$ture bone cells

4c)nge nutrients n' (stes (it) t)e bloo'


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Histology of Bone #issue Osteoclsts

Relese en3y/es t)t 'igest t)e /inerl co/*onents of bone/tri4 .resorption0

Regulte bloo' clciu/ le-el


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). Its cells are located in lacunae

Bone

Osteoblsts re /ost i//turecellsIncti-esi/*le s5u/ousActi-ecolu/nr or cuboi'l


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&arge multinucleated cells with acidophilic

cytoplasm that occupy *owship+s lacunae etched,by en$ymatic action, into the surface of bone that

is being resorbed.

steoclasts


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steoclasts


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-ormed by the fusion of monocytes (part of the

mononuclear phagocyte system.

steoclasts


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"hese cells secrete acids, collagenase and other

proteolytic en$ymes.

steoclasts


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Proteo

glycans

&lyco proteins


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Chondroitin sulfates form most of the organic

portion of bone matri.

/round Substance

Orgnic*roteoglycn

n'glyco*rotein6collgenty*e I

Inorgnicclciu/6*)os*)orus67n' P)os*)te crystl)y'ro4y *etiet crystls


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0. Canaliculi lin the lacunae and serve as a meansfor the passage of nutrients

Bone

i


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Collagen fibers gives tensile strength and resiliency to

bone.

-ibers

-ib


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"he collagenous fibers within a lamella are oriented

in the same plane1 fibers in ad2acent lamellae areoriented at right angles to these.

-ibers

B


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3. "he collagen fibrils are

organi$ed into lamellae

Bone

'

B


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4icroscopic eamination shows

Bone

steon

Concentric

&amellae

Central

(*aversian

Canal


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canaliculi

lacunae

ground

bone,

unstained

B


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called osteocytes, occupy lacunae and are

somewhat evenly distributed throughout the bone

tissue. 5

Cells

Bone

B


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called osteocytes, occupy lacunae and are

somewhat evenly distributed throughout the bone

tissue. 5"he cells conform to the shape of the lacunae and

send processes into canaliculi, where they form gap

2unctions with the processes of ad2acent cells. 5

Cells

Bone

B


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Cylindrical units of 6 #76 concentric lamellae

which surround a

central *aversian

canal.

%ach lamellae is 0 to 8

9m in thicness and its

fibers run in a spiral

fashion around the

canal.

*aversian Systems (steons:

Bone

B


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"he *aversian canal containscapillaries, venules, lymphatic vessels

and a loose connective tissue

containing osteoprogenitor cells.


Bone

Bone


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Compact bone # consistsof:

(7 concentric lamellae

arranged in *aversian

systems, and5

() Interstitial lamellae

between the *aversian

systems.

rgani$ation of lamellae:

Bone

Bone


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*aversian canals are orientedin the long ais of the bone.


Bone

Bone


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*aversian canals are oriented

in the long ais of the bone.

'olmann+s canals are

vascular channels that

connect the *aversian system

with the blood vessels in the

periosteum.


Bone

Bone


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Bone

Bone


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;emnants of *aversian systems that were partially

resorbed.

Interstitial &amellae:

Bone

Bone


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uter circumferential

lamellae lie net to the

periosteum and oriented

parallel to it. 5

Inner circumferential

lamellae lie net to the

endosteum.

Circumferential &amellae:

Bone


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(icroscopic

e$amination of bones)o(s primary% immature% or wo!en bone seconary% mature% or lamellar bone.

Pri/ry bone is t)e +rst bone tissue to **er in e/bryonic

'e-elo*/ent n' in frcture re*ir n' ot)er re*ir *rocesses8 It is c)rcteri3e' by rn'o/ 'is*osition of +ne collgen +bers6

in contrst to t)e orgni3e' l/ellr 'is*osition of collgen insecon'ry bone8

te/*orry

.eg6 ner t)e sutures of t)e 9t bones of t)e s:ull6 in toot)soc:ets6 n' in t)e insertions of so/e ten'ons06 is re*lce' in'ults by secon'ry bone tissue8

lo(er /inerl content .it is /ore esily *enetrte' by 4rys0 n' )ig)er *ro*ortion of osteocytes t)n in secon'ry bone tissue


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Histology of Bone #issue

Bone /y be ctegori3e' s;7o/*ct

!*ongy


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Histology of Bone #issue

)ompact Bone

Resists t)e stresses *ro'uce' by (eig)tn' /o-e/ent

7o/*onents of co/*ct bone re

rrnge' into re*eting structurl unitsclle' osteons or Ha!ersian systems

Osteons consist of centrl .H-ersin0

cnl (it) concentriclly rrnge'l/elle6 lcune6 osteocytes6 n'cnliculi


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Histology of Bone #issueSpongy Bone

Lc:s osteonsL/elle re rrnge' in lttice of

t)in colu/ns clle' trabeculae

!*ces bet(een t)e trbecule /:ebones lig)ter #rbecule of s*ongy bone su**ort n'

*rotect t)e re' bone /rro(He/o*oiesis .bloo' cell *ro'uction0 occurs

in re' bone /rro( of s*ongy bone

i l f i


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Histology of Bone #issueSpongy Bone


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Components

cells,

fibers

matri


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Ric:ets

• 7lciu/ 'e+ciencyt)e bone /tri4 'oes not clcify nor/lly

t)e e*i*)ysel *lte beco/es 'istorte' byt)e nor/l strins of bo'y (eig)t n'/usculr cti-ity8

Ossi+ction *rocesses )in'ere'6

t)e bones not only gro( /ore slo(ly butlso beco/e 'efor/e'8


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Osteo/lci

• 7lciu/ 'e+ciency in 'ults gi-esrise to osteo/lci .osteon = >r8

/l:i6 softness06• 'e+cient clci+ction of recently

for/e' bone

• *rtil 'eclci+ction of lre'yclci+e' /tri48


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Osteo*orosis

• i//obili3e' *tients

• *ost/eno*usl (o/en

• 'isese cuse' by 'efect inosteoclst function t)t results ino-ergro(t)6 t)ic:ening6 n'

)r'ening of bones• #)ic: n' 'ense/rble bones

histology of bone by dr.danish :d

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