blood cells morphology.ppt
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The morphology of Blood cells
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Composition of the blood
The circulating blood is composed of plasma
and cells. The cells are red cells(or erythrocytes),
white cells(or leucocytes) and platelets.
Blood cells can be identified in blood filmsstainedwith a mixture of basic and acidicdyes.
Normal white cells are divided intopolymorphonuclear leucocytes(orgranulocytes) and mononuclearcells.
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White blood cells
There are three types ofgranulocyte namedaccording to theirstaining characteristics inblood films. They areneutrophils,eosinophilsand basophils.
Mononuclear cells aredivided intolymphocytesandmonocytes.
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Neutrophils
The neutrophils in
the circulatingblood are mainlymature segmented
neutrophils.
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Band form Neutrophils
There are smallernumbers of cells ofneutrophil lineage with
non-segmented nuclei.
They are referred to asneutrophil band cellsorband forms. They areless mature thansegmented neutrophils.
An increased numberof band cells is referredto as a'left shift'.
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Eosinophil
One eosinophil -mature. Normalblood - 100X.
Orange colourgranules.
Bi-lobed nucleus.
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Basophil
One maturebasophil.
Blackish granules
overlying thenucleus.
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Normal lumphocytes
Lymphocytes are thesmallest WBC.
They have largecondensed nucleus,with a scanty bluishcytoplasm.
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Red cells
Normal red cells orerythrocytes show
only slight variationin size and shape.The blood filmshould be examined
in the area wherethe red cells aretouching but notoften overlapping.
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Red cells
. In this area many redcells have an area of
central pallor which maybe up to a third of thediameter of the cell. Thisis consequent on theshape of a normal red
cell, which resembles adisc that is thinner in thecentre.
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Platelets
Normal platelets arealso apparent. They
are small anuclearfragments betweenthe red cellscontaining small
purple-staininggranules.
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Platelet ribbon
A string of plateletsor Platelet Ribbon.This is theappearance of normalplatelets when beingshed by amegakaryocyte intothe marrow sinus.The ribbon thenbreaks up intonumerous smallplatelet fragments.
Normal blood - 100X
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Platelet aggregates
Platelet aggregates maybe
composed of apparentlyintact
platelets, degranulatedpale grey platelets or amixture of both, as in
this example. If theplatelet count is low it isessential to examine theblood film carefully forplatelet aggregates.
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Platelet satellitism
Platelet satellitismdescribes thephenomenon ofadherence of platelets towhite cells.
It is an in vitrophenomenon of no
clinical significance.However it is importantthat it is detected sincethe platelet count will befactitiously low.
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Nucleated epithelial cells
Extraneous non-haemopoietic cells aresometimes seen in bloodfilms. These includeepithelial cells which arereadily identified fromtheir abundant sky-bluecytoplasm and smallcentral nucleus. Theyare more often seen
if capillary blood isobtained by
percutaneous puncturethan when a film is
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Endothelial cells Endothelial cells are very
occasionally seen in filmsprepared from venousblood samples. They
have rather pleomorphicoval nuclei with agrooved surface. Thecytoplasm is scanty andthe cell outline is
irregular. They tend tooccur in clumps. It isimportant not to confusenormal endothelial cellswith carcinoma cells
which are also veryoccasionall seen in the
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Artefacts
Fixation artefact is theterm used for the
artefact that occurswhen there is water inthe methanol used forfixation of the bloodfilm.This leads to
refractile rings in redcells and makes it quiteimpossible to assess redcell morphology.
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Heat artefact
Inadvertent heating of ablood
sample, for exampleduring
transport in a hot car, canlead to a heat artefact.
Red cells bud off
vesicles andmicrospherocytes seen.
White cells disintegrateand
proteins coagulate,producing weakly
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Storage artefact
Prolonged storage of bloodbefore making the blood film,particularly storage at room
temperature,leads to storageartefact.
White cells become fragileand may form smear cells[deep red arrow].
Neutrophil nuclei round up
and form homogeneousround masses or a singlemass [blue arrow].These cellshave a resemblance to NRBC.
Red cells undergo an
echinocytic change orcrenation.