Anatomy and Physiology of WBC, Structure

WBC

1. 1
Department of Pharmacology SANJO
CPS Palakkad
LEUKOCYTES

2. Copyright 2009, John Wiley & Sons, Inc.
White Blood Cells/ Leukocytes
Have nuclei
Do not contain hemoglobin
Granular or agranular based on staining
highlighting large conspicuous granules
Granular leukocytes
Neutrophils, eosinophils, basophils
Agranular leukocytes
Lymphocytes and monocytes

3. Leukocytes (WBCs)
•least abundant formed element
–5,000 to 10,000 WBCs/L [4000 to 11000 cells/cu mm]
•Protect against infectious microorganisms and other
pathogens
•Spend only a few hours in the blood stream before migrating
to connective tissue
•Retain their organelles for protein synthesis
•GRANULES
–Granulocyteshavespecificgranulesthat
containenzymesandotherchemicals
employedindefenseagainstpathogens

5. GRANULAR AGRANULAR
Neutrophils
55 –70%
Phagocytize+digestbacteria
Eosinophils + Basophils
Involved in inflammatory + allergic
response
Polymorphonuclear
(many-lobed nucleus)
Monocytes
-very large + phagocytic (2 –8%)
-Indented nucleus
Lymphocytes
-matured in lymph thymus +
bone marrow
-responsible for immunity
-Procedure antibodies
Mononuclear
(have circular or indented nucleus)

6. Types of Leukocytes
•GRANULOCYTES
–NEUTROPHILS(60-70%)-polymorphonuclear leukocytes
•barely-visible granules in cytoplasm; 3 to 5 lobed nucleus
–EOSINOPHILS(2-4%)
•large rosy-orange granules; bilobed nucleus
–BASOPHILS(<1%)
•large, abundant, violet granules (obscure a large S-shaped nucleus)
•AGRANULOCYTES
–LYMPHOCYTES (25-33%)
•variable amounts of bluish cytoplasm (scanty to abundant);
ovoid/round, uniform dark violet nucleus
–MONOCYTES(3-8%)
•largest WBC; ovoid, kidney-, or horseshoe-shaped nucleus

7. Granulocytes
Neutrophils 10 µm Eosinophil 10 µm Basophil 10 µm
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all: © Ed Reschke

8. Agranulocytes
Lymphocyte
10 µm
Monocyte
10 µm
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both: Michael Ross/Photo Researchers, Inc.

9. GRANULOCYTE FUNCTIONS
•NEUTROPHILS-increased numbers in bacterial infections
–phagocytosis of bacteria
–release antimicrobial chemicals
•EOSINOPHILS-increased numbers in parasitic infections, collagen
diseases, allergies, diseases of spleen and CNS
–phagocytosis of antigen-antibody complexes, allergens, and inflammatory
chemicals
–release enzymes to destroy large parasites
•BASOPHILS -increased numbers in chicken pox, sinusitis, diabetes
–secrete histamine (vasodilator) –speeds flow of blood to an injured area
–secrete heparin (anticoagulant) –promotes the mobility of other WBCs in the
area

10. Functions of WBCs
–Usuallyliveafewdays
–Exceptforlymphocytes–liveformonthsor
years
–FarlessnumerousthanRBCs
–Leukocytosisisanormalprotective
responsetoinvaders,strenuousexercise,
anesthesiaandsurgery
–Leukopeniaisneverbeneficial
–Generalfunctiontocombatinvadersby
phagocytosisorimmuneresponses

11. Copyright 2009, John Wiley & Sons, Inc.
Emigration of WBCs
•ManyWBCsleavethe
bloodstream
•Emigration(formerly
diapedesis)
•Rollalongendothelium
•Sticktoandthensqueeze
betweenendothelialcells

12. Copyright 2009, John Wiley & Sons, Inc.
WBCs-Neutrophils
•Neutrophils and
macrophagesareactive
phagocytes
–Attractedbychemotaxis
•Neutrophilsrespondmost
quicklytotissuedamage
bybacteria
–Useslysozymes,strong
oxidants,defensins

13. Neutrophil function
1.Phagocytosis: 1
st
line of defense, ingest & destroya
bacteria.
2.Pyrogens & inflammatory cytokines: endogenous
pyrogen which is an important mediator of febrile
response to bacteria+ other regulation and inflam.
defense reaction

14. Monocytes
•Monocytestakelonger
toarrivebutarrivein
largernumbersand
destroymoremicrobes
–Enlargeanddifferentiate
intomacrophages
Copyright 2009, John Wiley & Sons, Inc.

15. Functions:
1.Roleinphagocytosis:capableofphagocytosingas
manyas100bacteria,largeparticlessuchasRBCs
&malarialparasites.
2.Precursoroftissuemacrophages:
Thematuremonocytestayinbloodonlyforfew
hours&thentheyleavebloodandenter
extravasculartissue,tobecometissuemacrophages.
3.Roleintumorimmunity:killtumorcellsafter
sensitizationbylymphocytes

16. 4.Synthesis of:
Complement & sis of biological substances:
PGE & clot promoting factors.
Also: Interleukin-1, Hemopoietic factors(G-CSF,
GM-CSF),TNF-α,
Binding proteins like transferrin,lysosomes,Proteases,
Acid hydrolases
5. Key role in the lymphocyte –mediated immunity
as ANTIGEN PRESENTING CELLS .

17. Copyright 2009, John Wiley & Sons, Inc.
WBCs-Basophil
•Basophil leave
capillariesandrelease
granules containing
heparin,histamineand
serotonin,atsitesof
inflammation
–Intensifyinflammatory
reaction
–Involved in
hypersensitivityreactions
reactions(allergies)

18. Functions:
1.Mildphagocytosis:
2.Roleinallergicreaction:
Basophils release histamine, bradykinin,
no. of lysosomal enzymes,
slow reacting substance of anaphylaxis (SRS-A) serotonin
(5HT).
These substances cause local vascular & tissue reactions that
cause many allergic manifestations.
3.Liberatesheparinwhich
i.Actsasanticoagulant&keepsbloodinfluidstate.
ii.Activatestheenzymelipoproteinlipase:removesfat
particlesfromthebloodafterfattymeal.

19. Eosinophils
•Eosinophils leave
capillariesandenter
tissuefluid
–Releasehistaminase,
phagocytizeantigen-
antibodycomplexesand
effectiveagainstcertain
parasiticworms
Copyright 2009, John Wiley & Sons, Inc.

20. Functions:
1.Mildphagocytosis:becauselessmobilethanneutrophils
2.Eosinophilscollectatthesitesofallergicreactions&
detoxify
Inflammationinducingsubstancesbydegradingthe
mediators(e.g.histamine,bradykinin)
3.Theyenterthetissues&arespeciallyabundantinthe
mucosaofrespiratorytracts,GIT,urinarytract,where
theyprovidemucosalimmunity
4.Eosinophilsattackparasitesthataretoolargetobe
engulfedbyphagocytosis.
5.Eosinophilgranulesreleasechemicals(peroxidase)
whicharetoxictolarvaeofparasites

21. AGRANULOCYTE FUNCTIONS
•LYMPHOCYTES -increasednumbersindiverse
infectionsandimmuneresponses
–destroycells(cancer,foreign,andvirallyinfectedcells)
–“present”antigenstoactivateotherimmunecells
–coordinateactionsofotherimmunecells
–secreteantibodiesandprovideimmunememory
•MONOCYTES -increasednumbersinviralinfections
andinflammation
–leavebloodstreamandtransformintomacrophages
•phagocytizepathogensanddebris
•“present”antigenstoactivateotherimmunecells-antigen
presentingcells(APCs)

22. Copyright 2009, John Wiley & Sons, Inc.
Lymphocytes
•Lymphocytes are the major soldiers of the
immune system
–B cells –destroying bacteria and inactivating their
toxins
–T cells –attack viruses, fungi, transplanted cells,
cancer cells and some bacteria
–Natural Killer (NK) cells –attack a wide variety
of infectious microbes and certain tumor cells

23. B lymphocyte: originate from BM(primary lymphoid organ),
mature also in secondary lymfoid organs: lymphnode,
spleen, MALT etc.
1.Involved in the humoral immunity: Antibody production,
antigen presentation.
T lymphocyte: processed in thymus, concerned with the
cellular immunity: defensive role againstviral & bacterial
infections and tumor cells
CD4: T helpers, function: Th0, Th1, Th2
CD8: cytotoxic T cells
NK cells: direct cytotoxicity: CD56, CD57

24. LEUKOCYTE LIFE CYCLE
•LEUKOPOIESIS–production of white blood cells
–pluripotent stem cells –(PPSCs)
•myeloblasts–formneutrophils,
eosinophils,basophils
•monoblasts-formmonocytes
•lymphoblastsgiverisetoallformsof
lymphocytes
•red bone marrow stores and releases granulocytes and
monocytes

25. •circulatingWBCsdonotstayin
bloodstream
–GRANULOCYTES leavein8hoursand
live5dayslonger
–MONOCYTES leavein20hours,
transformintomacrophagesandlivefor
severalyears
–LYMPHOCYTES providelong-term
immunity(decades)beingcontinuously
recycledfrombloodtotissuefluidtolymph
andbacktotheblood

26. Leukopoiesis
leaves
Lymphoblast
B prolymphocyte
B lymphocyte
T lymphocyte
NK cell
T prolymphocyte
NK prolymphocyte
Monoblast Promonocyte Monocyte
Basophil
Eosinophil
Neutrophil
Pluripotent
stem cell
Colony-forming
units (CFUs)
Precursor
cells
Mature
cells
Eosinophilic
myelocyte
Eosinophilic
promyelocyte
Eosinophilic
myeloblast
Eosinophilic
CFU
Basophilic
CFU
Neutrophilic
CFU
Monocytic
CFU
Lymphocytic
CFU
Basophilic
myeloblast
Neutrophilic
myeloblast
Neutrophilic
promyelocyte
Basophilic
promyelocyte
Basophilic
myelocyte
Neutrophilic
myelocyte
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