blood cells morphology.ppt

8/11/2019 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.

blood cells morphology.ppt

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