Blood Physiology Notes by Ms Raj Laxmi.pdf

Blood chapter physiology include all about chapter related

2. Introduction
Bloodmaybedescribedasaspecialized
connectivetissueinwhichthereareliquid
intercellularsubstancesknownasplasmaand
formedelements,liketheredbloodcells,the
whitebloodcellsandtheplateletsthatare
suspendedintheplasma.

3. Colorofblood:Arterialbloodisscarletredincolor.The
venousbloodappearspurpleredincolor.
Totalbloodvolume:5-6L(8%ofbodyweight)
Specificgravity:1.050-1.061(totalblood)
pHofblood:7.4±0.05.
Viscosity:Viscosityofbloodisanimportantfactor,sinceit
determinestheperipheralresistanceofthebloodflowthrough
thebloodvesselsandthushelpstomaintainbloodpressure.It
isfourtofivetimesthatofwater.Humanbloodisfivetimes
moreviscousthandistilledwater.Theviscosityofthewhole
bloodismainlyduetocellsandthatofplasmaisdue
toplasmaproteins
Physical Characteristics

4. Function of Blood
I.Transportation-
Bloodtransportsgases(O2,CO2),nutrients(glucose,
aminoacidandfattyacid),wasteproduct(urea,uricacid
andcreatinine),hormones(GHT3,T4,TSH)andheat
fromonepartofbodytootherpartofbody.
Haemoglobin(alsocalledrespiratorypigment)combines
withoxygenandformoxyhaemoglobinandwithcarbon
dioxideformcarbaminohaemoglobin.

5. II.Regulation–
Bloodhelpstomaintainhomeostasis(tendencyto
maintainequilibrium)inallbodyfluids,examplesare
regulationofwaterbalance,acidbasebalance&body
temperatureregulation
III.Protection–
Bloodprotectusfromexcessivehemorrhageby
clottingafteraninjury.
WBCandantibodiespresentintobloodprotectusby
infectiousagents.

6. Thegeneralcompositionofthewholeblood
Isasfollows:
Wholebloodcells:
Redbloodcorpusclesorerythrocytes(RBC)
Whitebloodcorpusclesorleukocytes(WBC)
Plateletsorthrombocytes
Plasma:
Obtainedfrombloodaftercentrifugationoraddition
Water:91-92%andsolids(8-9%)
Inorganicconstituents(0.1%):Theseincludesodium,
potassium,calcium,magnesium,phosphorus,iron,copper,
etc.,constituting0.9%.
Components of Blood

7. Organicconstituents(8%):
Proteins7%:Serumalbumin,serum
globulinfibrinogen,prothrombin,
etc.
Nonproteinnitrogenous(NPN)
substances(1%):Urea,uricacid,
xanthine,hypoxanthine,creatine,
creatinine,ammonia,aminoacids,
etc.
Carbohydrate:Glucose,etc.
Fats:Neutralfat,phospholipid,
cholesterol,cholesterosis,etc.
Other substances: Internal
secretions,antibodiesandvarious
enzymes(amylases,proteases,
lipases,phosphatases,etc.).

8. Haematopoiesisistheprocessofformationofblood
cells,i.e.,RBCs,WBCsandplatelets.Ittakesplace
inthebonemarrow,liverandspleen
FORMATION OF BLOOD

9. •Whenalltypesofcellsremovedfrombloodthan
remainingstrawcolouredliquidcalledplasma.
•Orawateryliquidmatrixthatcontainsdissolved
substancecalledplasma(bloodcontain50to60%water).
•Thewateryportionofthebloodaftercoagulationcalled
serum[serum=plasma-fibrinogen).
•Serumnotcontainsclottingfactors(fibrinogen)because
fibrinogenconvertedintofibrin&usedintoblood
clotting.
Blood plasma

10. CONT…………………
•Proteinpresentinplasmaiscalledplasmaprotein.
•Plasmaproteinplaysanimportantroleinmaintaining
bloodcolloidal(normalvalue25-30mmofHg).
•Albuminissmallestandmostnumerousofprotein,play
majorroleinmaintainingoncoticpressureofblood.
•Plasmaproteinsaresynthesizedbyhepatocytesexcept
gammaglobulinprotein

11. Bone marrow
Bonemarrowisthecellulo-vasculartissueoccupyingthemedullarycavitiesandthe
cancellousspacesofthebone.
Activemarrowintheadultisesmeatedtobefrom3.5%to6%ofbody
weight.Thevolumeofthemarrowis70mlatbirthandabout4000mLintheadult.
Inadults,onlyabouthalfofthemarrowisinanactivestate,knownasredbone
marrow,theremainderbeinginactive-yellowbonemarrow.
Bytheageof20,themarrowincavitiesofalllongboneswithexceptionof
theupperendsofhummersandfemurbecomesinactive.Hence,inadults,redmarrow
ispresentintheaxialskeleton:
skull,pelvis,ribs,sternum,vertebrae;andproximalendsoffemur
andhummers.
Inanewbornbaby,allbonemarrowareredandasageincreases,redbone
marrowremainsactiveonlyinmembranebones.Inanewborn,ifhematopoiesisis
goingonoutsidethebonemarrow,i.e.,intheliver,spleenandlymphnodes,
itiscalledextramedullaryhematopoiesis.Ifthereisneedofexcessive
hematopoieticactivity,yellowbonemarrowhasacapacitytobe
reactivatedandconvertedintoredbonemarrow(seeninsevere
hemolysis).

12. Atandafterbirth,bloodcells(redbloodcellsareactivelymanufactured
here,hencethecolormostwhitebloodcells,andplatelets)areformed
onlyinthebonemarrow.Allbloodcellsoriginatefrompluripotentstem
cells,whichareuncommittedstemcellsandgothroughseveralstagesof
development.These,thepluripotentstemcellsdifferentiateintodifferent
committedstemcellscalledtheprogenitorcells.
Redbonemarrow:Redcellsareactivelymanufacturedhere,hencethe
color.Redbonemarrowisvascularandrichinhematopoieticstemcells.
Infetalstage,mostofthebonescontainredbonemarrow.But,withthe
advancementofageandinpostnatallife,theredbonemarrowisonly
locatedintheupperendsofhummersandfemur,thebonesofskulland
thorax,thevertebraeandcrestoftheinnominate/iliumbonesofthe
pelvis.

13. Yellowbonemarrow:Itismadeoffatandalittlereticulartissuewithblood
vessels.Becauseyellowbonemarrowhasfatcells,soitisyellowincolor.
Here,redcellsarenotmanufactured.Intheadultlife,theyoccupythe
spaceswhereredmarrowisabsent
FormationofBoneMarrow:-Frombirthuptothe4thyear,allbones
containredbonemarrow.By7years,themarrowbecomeslessactive
andispaleredincolor.Between10and14years,apatchofyellowbone
marrowappearsinthedistalendsoftheshaftsofthelongbonesand
graduallyextendsonbothsides.
Attheageoftwenty,theentireredbonemarrow
ofthelongbonesisreplacedbyyellowbonemarrowexcepttheupper
endsoffemurandhumors.Throughoutadultlife,this
distributionpersists.

14. FunctionsofBoneMarrow:-
Hematopoietic(hemopoietic)function(productionandreleaseof
bloodcells):Productionofmyeloidelementsistheimportant
functionofbonemarrow.Ithasbeendescribedthatredbone
marrowisactiveandhasthecapacityofformingredcellsaswell
asotherbloodcells.
ErythroplasiaordestructionofRBCs:Inthebonemarrow,not
onlythebloodcellsareformedbutalsotheabnormal,imperfect,
damagedandagedRBCsaredestroyed.

15. Storagefunctions:Bonemarrowisanimportantsiteforstorageof
ironintheformofferritinandhemosiderin.Theseformsofiron
comefromfoodsourcesastransferrinandalsofromdestructionof
RBCthroughphagocytosis.Thesestoredironsareeasilyutilizedfor
thesynthesisofhemoglobin.
Reticuloendothelialfunction:Bonemarrowplaysanimportantrole
intheinactivationoftoxinsorothertoxicsubstancesofthebody.
Osteogenicfunction:Thecellularelementswhichtakepartinthe
formationofboneareformedinthemarrow.Theosteoclast,
osteoblast,osteocyteandendosteumofbloodvesselsare
formedwithinthemarrow

16. Hematopoiesisanderythropoiesisaretwopathwaysinvolvedinthe
synthesisofbloodcells.
HEMATOPOIESIS VERSUS ERYTHROPOIESIS
Haematopoiesis
Theprocessofformationofbloodcells,i.e.,RBCs,WBCsandplateletsis
calledhematopoiesisandthesiteswhereitoccursareknownas
hematopoietictissuesororgans(bonemarrow,liver,spleen).Thecells
responsibletodofunctionofhematopoiesisarefirstseeninyolksacof
embryointhirdweekofembryonicdevelopmentandthesecellsareknown
ashematopoieticstemcellsHematopoiesisiscompletedthroughfive
processes:
erythropoiesis,
lymphopoiesis,
granulopoiesis,
monopoiesis
thrombopoiesis.

17. Erythropoiesis haematopoiesis
Erythropoiesisisthedifferentiation
andmaturationoferythrocytes.
Haematopoiesisisthedifferentiationandmaturation
ofbloodcellsfromHSCs.
Basicallyregulatedbyerythropoietin.Regulatedbyavarietyofgrowthfactors.
Notypesoferythropoiesisfound Fivetypearefoundsinhaematopoiesis:
erythropoiesis,lymphopoiesis,granulopoeisis,
monopoiesisandtharmbopoesis
Proerythroblastisthefirstcommitted
cellinerythropoiesis.
Proeythroblast,lymphoblast,myeloblastand
megakaryoblastarethefirstcommittedcellsof
haematopoiesis.
Erythropoiesisisbasicallyregulated
byerythropoietin.
Heantopoesisisregulatedbyavarietyofgrowth
factors..

18. Therearethreetypesofbloodcellsinblood-
(1)RBCorErythrocytes
RBClacksanucleusandotherorganellessoitcannotdivideandhave
limitedlifespanof120days
ThediameterofanRBCis72m
RBCisdiscshapedbiconcavecell
SurfaceareaofanRBC120squareµm&volumeofanRBC90cubicum
ThetotalsurfaceareaofallRBCsofanaverageadultis3820sq.meteror
about2000timesmorethantheexternaltotalbodysurfacearea
RBC'Sredcolorisduetopresenceofporphyrinpigmentpresentinto
hemoglobin

19. Whole body
Blood (8%) Other tissue(92%)
Plasma(55%) Other Solutes(1.5%) Water (91.5%)
Albumin
(54%)
Globulin
(38%)
Fibrinogen
(7%)
All other
Proteins (1%)
Gases
(O2, CO2, N2)
Nutrients
(Glucose, Amino acid)
Waste product
(Urea, Uric acid)
Harmone electrolytes
(Na+, Ka+, Cl etc.)
RBC (4.8-5.4 Million
cell/micron l )
WBC (4000-11000
cell/micron l )
Platelets (1.5 lac-4.5 lac
cell/micron l )
Neutrophils
(60-70 %)
Eosinophils
(2-4%)
Monocyte
(3-8 %)
Basophils
(0.5-1 %)
Lymphocyte
(20-25%)
B -Lymphocyte T-Lymphocyte
Young Neutrophils called bands
Old Neutrophils called Polymorphonuclear leukocytes
(PMN)
Plasma(55 %) Cell (45 %)

20. Pluripotent Hemopoietic Stem Cell (PHSC)
Myeloid stem cell Lymphoid Stem cell
CFU-E (Diameter 20 micron m) CFU-M CFU-GM
Proerythroblast
Reticulocyte
(immature RBC)
RBC (diameter 7.2 micron m)
Megakaryocyte
Megakaryocyte
Thrombocyte
Eosinophils
Monocyte
Basophils
B-Lymphoblast
B -Lymphocyte
T-Lymphoblast
T-lymphocytes
Myeloblast
Neutrophils
Eosinophilic Myeloblast
Basophilic Myeloblast
Monoblast
CFU-E colony Forming Unit, E= erythrocytes GM= granulocyte and monocyte
M= Megakaryocyte

21. II.WBC or leukocytes
WBC act as a defence against infection.
WBC is a nucleated cell
WBC can divide into two major groups
a.Granular leukocytes (neutrophil, eosinophil and basophiles)-
Cytoplasm of granular leukocytes contains granules
Granules contain some enzyme (e.g. proteases) which destroyed
microorganism
b. Agranular leukocytes (lymphocytes and monocyte)-
Granules are not visible under a light microscope,

22. (i)Eosinophil(eosinlovingcells,diameter10-14µm)
Itstainswithanacidicdye(eosin)andgiveredorangecolon.
Playimportantroleinparasiticinfestationandallergicreaction(ii)
(ii)Basophil(diameter8-10µm)
Itstainswithbasic(methyleneblue)dyeandgiveblue-purplecolour.
Itplaysimportantroleinhealingprocess
(iii)Neutrophil
Itstainswithacidic(eosin)andbasic(methyleneblue)dyeandgive
violetcolour
ThisstaincalledLeishman'sstain
Olderneutrophilcalledpolymorphonuclearleukocytes(PMN)
becauseitcontainsmanynuclearlobes(2-5lobes)
Youngerneutrophilcalledhandsbecausetheirnucleuslookslikerod
shaped
Neutrophilprovidefirstlineofdefenceofbody.

23. (iv)Lymphocytes(diameter7-12μm)
Lymphocytesareresponsibleformuchofthebody'simmune
protection
Lessthan1%oflymphocytesarepresentinthecirculating
bloodandtherestlieinthelymphnodes,spleenandother
lymphoidorgans,wheretheycanmaximizecontactwith
foreignantigens
Basedonplaceofmaturationandtheirfunction,lymphocytes
dividedintotwotypes,e.g.

24. (a)T-Lymphocytes(75%oftotallymphocyte)
FinalmaturationofT-lymphocytesoccursinthymusgland,soit
calledT-lymphocytes
T-lymphocytesareresponsibleforourbody'scellularimmunity(T-
cell-mediatedimmunefunctionsrequiringcellinteractions)
Itmainlyattacksvirusesandtransplantedorgancells
Lymphocytesareplayingroleofmajorsoldiersinourbody's
immunesystembattle
TherearefourtypesofT-Lymphocytesinhumanbody,whichare
identifiedbyuniqueproteingroupsonthecellsurfacecalled
clustersofdifferentiation(CD)

25. (1)HelperTcellsorCD4TcellsorinducerTcells–
TheseTcellsstimulateorregulateactivityofotherTcellsduring
infectionorattackofforeignbody.
AHIVpositivepersondiagnoseAIDSandstartedART
(antiretroviraltherapy)whentheCD,countisbelow200-
cells/mm²ofblood.
NormalcountofCD'cellsare500to1500cells/mm3ofblood
(average950cell/mm)
(2)CytotoxicT-lymphocytesorkillerTlymphocytesorCDS'Tcells
Itdirectlyattacksthemicroorganismanddestroyedthemby
lysosomalenzymes
(3)SuppressorT-lymphocytes-
ItsuppressestheactivityofkillerTlymphocytes
(4)MemoryT-lymphocytes-
Itremainsintolymphoidtissueandkeepsmemoryforinfectionin
nexttimebysameorganism

26. (b)B-Lymphocytes-
Finalprocessofmaturationoccursintoliver(duringfoetallife)
andbonemarrow(afterbirth)
BlymphocytesformhumoralimmunityorBcellsimmunity
Humoralimmunitymeans,resistancepowerofbody(immunity)
byantibodiesorimmunoglobulins.
Blymphocytestransformintoplasmacellandplasmacell
produceaproteincalledGamaglobulins
ProteinGamaglobulinformantibodiesorimmunoglobulin
Antibodiesfightagainstinvadingorganism,especiallybacterial
infection

27. B LYMPHOCYTES
Plasma cell Memory B cell
Keep memory for next
infection by same organism
Produces antibodies or
immunoglobulins
(IgG, IgM. IgA, IgE, IgD)

28. Antibodiesorimmunoglobulin's–
Therearefivetypeofantibodiesorimmunoglobulinin
ourbody
(1)ImmunoglobulinAlpha(IgA)-
Itmainlyfoundintobreastmilk(colostrum),sweat,
tear&saliva
Itprovideslocalimmunity
(2)ImmunoglobulinGama(IgG)-
Itismostabundant(80)immunoglobulin,
Itistheonlyclassofantibodytocrosstheplacenta
frommothertofetus(antibodyDisIgG)
Itindicateschronicinfectionbecauseitappearslater
intoserumafteraninfection

29. (3)ImmunoglobulinMu(IgM)-
Itindicatesacuteinfectionbecauseitsecretedfirstbyplasmacells
afteraninfection
AntibodyAandantibodyBareIgM
IgMishavingapentamericstructurebecauseitconsistsof5
immurioglobulinsubunits.
IgMalsocalled'millionairemoleculebecauseitisheavymolecule
withamolecularweight900.000to10,00,000.
(4)Immunoglobulinepsilon(IgE)–
Itinvolvesintoallergicandhypersensitivity(anaphylactic)
reaction.
(5)Immunoglobulindelta(IgD)-
Itsecretesintoverylessamountanditisnotsignifican

30. (V)Monocyte(LargestWBC,diameter14-18µm)
Itcontainsusuallykidney-shapedorhorseshoe-shapednucleus
Monocytecirculatesinthebloodstreamforabout24hourandthen
moveintotissues,wheretheyenlargeanddifferentiateinto
macrophages
Somemicrophagefixedintoparticulartissuesocalledfixed
microphage,examplesarekupffercellsintoliver,microgliaintoCNS,
alveolarcellintolungsetc.
Somemicrophagesroamintotissuethroughblood,socalled
wanderingmacrophage
Macrophageandneutrophilsinvolveintoprocessofphagocytosis.
Phagocytosisisathree-stageprocessbywhichphagocytes
(neutrophils,monocyteormacrophages)engulfanddestroy
microorganisms,otherforeignantigensandcelldebris

31. Leukocytosis-
IncreaseWBCCountabove11000cells/μl
Cause-Infection,allergy,heavyexercise,anaesthesia,surgeryetc.
Typesofleukocytosis–
Increaseneutrophil(neutrophilia)-Acutebacterialinfection,highstress,
burnetc.
Increaseeosinophil(eosinophilia)-Allergy,allergicinfection(asthma)&
parasiticinfectionlikemalaria,filariasis
Increasebasophil(basophilia)-Leukemia,canceretc.
Increasemonocyte(monocytosis)-Chronicinfectionslikefungal&
tubercular
Increaselymphocyte(lymphocytosis)-Chronicbacterialinfectionandall
viralinfection

32. Leukopenia–
AbnormallowlevelofWBCbelow4000cell/μl
Itisalwaysaharmfulcondition
Cause-Radiation,anaphylacticshock,chemotherapy,
typhoid,paratyphoid&cirrhosisofliver

33. (III)Plateletorthrombocyte-
Plateletsareformedbysplintingmegakaryocytesinto
2000to3000fragments
Plateletsarenon-nucleated,colourless,discshaped
fragmentofcells
Diameterofplatelets-2to4μm
Volumeofplatelets-7.5cubicmicron
Plateletshaveshortlifespanabout5to9days
Deadplateletsareremovedbyfixedmacrophagespresent
intospleenandliver

34. Plateletshavethreeimportantproperties
(i)Aggregation(Responsetovascularinjury)
(ii)Aggregation(Stichofeachother)
(iii)Agglutination
Byabovethreepropertiesplateletshelptostopbloodloss
fromdamagedbloodvesselsbyformingaplateletplug
Decreasenumberofplatelets(calledthrombocytopenia)
increasebleedingtendencyandincreasenumber(called
thrombocytosis)causethrombusformation

35. Hemostasis(stoppingofbleeding)
Itinvolvesthemechanisms:
(1)Vasoconstriction-
Whenvein,artery&arteriolesaredamaged,thecircularsmooth
musclesintheirwallcontractandstopbleeding.
(ii)Plateletplugformation
Plateletsaresticktodamagedbloodvessels&formplateletplug
(iii)BloodclottingorCoagulation–
Whenbloodcomesoutformbloodvesselitbecomesajellylikemass
(clot)afterfewminutesthisprocessiscalledcoagulationorblood
clotting

36. Clotting factor
Thosesubstancenecessaryforclottingarecalledclotting
factor.
Itnamedafterscientistwhodiscoveredthemoraspertheir
activityexceptIXth.
Clottingfactorsalsoidentifiedbyromannumeralsthat
indicatetheorderoftheirdiscovery

37. Clottingfactorsare-
I-Fibrinogen
II-Prothrombin
III-Tissuefactor(thromboplastic)
IV-Ca++
V-Labile/factor
VI-Absence
VII-Stablefactor
VIII-AntihemophilicfactorA
IX-ChristmasfactororAHF-B
X-StuartProwarfactor
XI-Plasmathromboplasticantecedent
XII-Hagemanfactor
XIII-Fibrinstabilizingfactor

38. Blood group and blood types
ABOsystem
KL.Landsteiner(Austrion-boUSbiologist,Nobelprizewinnerin
medicinein1930)discoveredbloodgroupsin1900,basedon
presenceofantigenoncellmembraneofRBC.
Hefoundtwotypeofantigen(agglutinogenAandBoncell
membraneofRBCandtwotypesofantibody(agglutinin)AandB
(alpha&betaantibodies)intheplasma.
Antibodiesareproducedonly2to3monthsafterbirth

41. ABOincompatibility-
Anantigen-antibodyimmuneresponsetoinfusionofanother'sred
bloodcells
Transfusionreactionsoccurmostcommonlyinpeoplewithtype
blood,whichcarriesnoantigensontheredbloodcellsand
containsbothanti-Aandanti-Bantibodies.
Intoobstetricstransplacentalfetal-maternaltransfusionoccurs
whenfetalbloodcellsescapeintothematemalcirculation,which
causeantibodyformation.
Maternalantibodiesthencrosstheplacentaintothefetal
circulation,attackanddestroyredbloodcells,whichisevidenced
byneonatalhyperbilirubinemiaandjaundice

42. RhfactororRhsystem
Rhantigen(anantigenoftencalledD)wasfirstfoundoncell
membraneofRBCofRhesusmonkeyin1940byKarl
LandsteinerandAlexander'swiener,soitwasnamedasRh
factor.
Persons(about85%)havingRhantigenorDAntigenare
calledRhpositive
Persons(about15%)nothavingRhantigenorDantigenare
calledRhnegative
Thereisnonaturalantibodyforthisantigen

43. Cont.………………………
PeoplewithOnegativebloodgrouparecalleduniversal
donors
PeoplewithABpositivebloodgrouparecalleduniversal
recipients
IfanindividualwithRhnegativebloodreceivesa
transfusionofRh+blood,anti-Rhantibodiesform
SubsequenttransfusionsofRhbloodmayresultinserious
transfusionreactions(agglutinationandhemolysisofred
bloodcells).

44. Cross matching
Major cross matching -The process of mixing a sample
of the donor's red blood cells with the recipient's serum.
Minor cross matching-The process of mixing a sample of
the recipient's blood with the donor's serum.
It is done before transfusion to determine compatibility
of blood.