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8/6/2019 Handouts Blood F11
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BIO202BloodPartIaBloodCompositionandFormedElementsFunctionsandCompositionofBlood Bloodhelpsmaintainhomeostasisinseveralways:
Transportofgases,nutrients,waste
products
Transportofprocessedmolecules
Transportofregulatorymolecules RegulationofpHandosmosis
Maintenanceofbodytemperature
Protectsagainstforeignsubstancessuchas
microorganismsandtoxins
Bloodclottingpreventsfluidandcellloss
andispartoftissuerepair
FunctionsandCompositionofBlood Bloodisaconnectivetissueconsistingofplasma
andformedelements
Bloodisthebodysonlyfluidtissue
Itiscomposedofliquidplasmaandformed
elements
Formedelementsinclude:
Erythrocytes,orredbloodcells(RBCs)
Leukocytes,orwhitebloodcells(WBCs)
Platelets
Hematocrit: thepercentageofRBCsoutofthe
totalbloodvolume
FunctionsandCompositionofBlood Bloodisasticky,opaquefluidwithametallictaste
Colorvariesfromscarlettodarkred
ThepHofbloodis7.357.45
Temperatureis38C
Bloodaccountsforapproximately8%ofbody
weight
Averagevolume:56L(1.5gallons)formales,and
45Lforfemales
Plasma Paleyellowfluidcontainingover100solutes
Mostlywater(91%)
Proteins(7%) Albumin(58%oftheplasmaproteins)
Helpsmaintainosmoticpressure
Globulins(38%oftheplasmaproteins)
Immunity: antibodiesandcomplement
Transport: bindtomoleculessuchas
hormones
ClottingFactors
Fibrinogen(4%oftheplasmaproteins)
Convertedtofibrinduringclotformation
Othersubstances(2%)
Ions(electrolytes): sodium,potassium,
calcium,chloride,bicarbonate
Nutrients: glucose,carbohydrates,amino
acids
Wasteproducts: lacticacid,urea,creatinine
Respiratorygases: oxygenandcarbondioxide
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FormedElements Erythrocytesorredbloodcells(RBCs)
About95%offormedelements
RBCshavenonucleiororganelles
Leukocytesorwhitebloodcells(WBCs)
Mostoftheremaining5%offormedelements
OnlyWBCsarecompletecells
FivetypesofWBCs
Platelets
Cellfragmentsformedbymegakaryocytes
Importantforbloodclotting
ProductionofFormedElements Hemocytoblastsgiverisetoallformedelements
Mostbloodcellsdonotdivide
Hematopoiesis:
blood
cell
production
Occursindifferentlocationsbeforeandafterbirth
Fetus
Liver,thymus,spleen,lymphnodes,andredbonemarrow
Afterbirth
Intheredbonemarrowofthe
Axialskeletonandgirdles
Epiphysesofthehumerusandfemur
Growthfactorsdeterminethetypeofformedelementderivedfromthestemcell
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BloodPartIbRedBloodCellsandWhiteBloodCellsRedBloodCells(RBCs) Biconcavediscs,anucleate,essentiallynoorganelles
RBCsarededicatedtorespiratorygastransport
Filledwithhemoglobin(Hb),aproteinthatfunctionsingas
transport
RBCsareanexampleofhowstructurefitsfunction
Biconcave
shape
has
a
huge
surface
area
relative
to
volume
Structuralcharacteristicscontributetoitsgastransport
function
BiconcaveshapealsoallowsRBCstobendorfoldaround
theirthincenter
Giveserythrocytestheirflexibility
Allowthemtochangeshapewhenmovingthrough
capillaries
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RedBloodCells Hemoglobin(Hb)consistsof
Theproteinglobin,madeupoftwoalphaandtwobetachains,eachboundtoahemegroup
Eachhemegroupbearsanatomofiron,whichcanbindtooneoxygenmolecule
Hememoleculestransportoxygen(ironisrequired)
Oxygencontentdeterminesbloodcolor
Oxygenated: brightred
Deoxygenated: darkerred
Globinmoleculestransportcarbondioxide
OneRBCcontains250millionHbgroupsthusitcancarry1billionmoleculesofO2
RedBloodCells TransportofOxygenandCarbonDioxide
Oxygen
Transportedboundtohemoglobin~98.5%
Dissolvedinplasma~1.5%
EachHbmoleculebindsfouroxygenatomsinarapidandreversibleprocess
Carbondioxide
Dissolvedinplasma~7%
Transportedasbicarbonate(HCO3)~70%
Chemicallyboundtohemoglobin~23%
RedBloodCells TransportandExchangeofCarbonDioxide
CarbondioxidediffusesintoRBCsandcombineswithwatertoformcarbonicacid(H2CO3),whichquickly
dissociatesintohydrogenionsandbicarbonateions
InRBCs,carbonicanhydrasereversiblycatalyzestheconversionofcarbondioxideandwatertocarbonicacid
CO2 + H2O H2CO3 H+ + HCO3
Carbon
dioxideWater
Carbonic
acid
Hydrogen
ion
Bicarbonate
ion
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Erythropoiesis Ahemocytoblastistransformedintoaproerythroblast
Proerythroblastsdevelopintoearlyerythroblasts
Ejectionofthenucleusfromlateerythroblastsandleadstoformationofreticulocytes
Reticulocytesarereleasedfromtheredbonemarrowintothecirculatingblood,whichcontains~13%reticulocytes
Reticulocytesthenbecomematureerythrocytes
Erythropoiesis Circulatingerythrocytes: Thenumberremainsconstantandreflectsa
balancebetweenRBCproductionanddestruction
ToofewRBCsleadstotissuehypoxia
ToomanyRBCscausesundesirablebloodviscosity
Erythropoiesisishormonallycontrolledanddependsonadequate
suppliesofiron,aminoacids,andBvitamins(folateandB12)
Erythropoietin(EPO)releasebythekidneysistriggered
by
HypoxiaduetodecreasedRBCs
Decreasedoxygenavailability
Increasedtissuedemandforoxygen
Enhancederythropoiesisincreasesthe
RBCcountincirculatingblood
Oxygencarryingabilityoftheblood
RecyclingofRBCs Thelifespanofanerythrocyteis100120days
OldRBCsbecomerigidandfragile,andtheirHbbeginsto
degenerate
DyingRBCsareengulfedbymacrophageslocatedinthe
spleenorliver
Hemeandglobinareseparatedandtheironissalvagedfor
reuse
Globin
chains
are
broken
down
to
individual
amino
acids
andaremetabolizedorusedtobuildnewproteins
Ironreleasedfromhemeistransportedtotheredbone
marrowandisusedtoproducenewhemoglobin
Hemebecomesbilirubinthatissecretedinbile
Intheintestinesbilirubinisconvertedbybacteria
intootherpigments
Givesfecesitsbrowncolor
Givesurineitsyellowcolor
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ErythrocyteDisorders Anemia:bloodhasabnormallylowO2carryingcapacity
Asignratherthanadiseaseitself
BloodO2levelscannotsupportnormalmetabolism
Accompaniedbyfatigue,paleness,shortnessofbreath,andchills
CausesofAnemia Insufficienterythrocytes
Hemorrhagicanemia:acuteorchroniclossofblood Hemolyticanemia:RBCsruptureprematurely
Aplasticanemia:destructionorinhibitionofredbonemarrow
Lowhemoglobincontent
Irondeficiencyanemia
Secondaryresultofhemorrhagicanemiaor
Inadequateintakeofironcontainingfoodsor
Impairedironabsorption
Perniciousanemia
DeficiencyofvitaminB12
LackofintrinsicfactorneededforabsorptionofB12
TreatedbyintramuscularinjectionofB12orapplicationofNascobal
CausesofAnemia Abnormalhemoglobin
Thalassemias
Absentorfaultyglobinchain
RBCsarethin,delicate,anddeficientinhemoglobin
Sicklecellanemia
Defectivegenecodesforabnormalhemoglobin(HbS)
CausesRBCstobecomesickleshapedinlowoxygensituations
ErythrocyteDisorders Polycythemia:excessofRBCsthatincreasebloodviscosity
Resultsfrom:
Polycythemiaverabonemarrowcancer
SecondarypolycythemiawhenlessO2isavailable(highaltitude)orwhenEPOproductionincreases
Blooddoping
WhiteBloodCells Onlybloodcomponentsthatarecompletecells
ArelessnumerousthanRBCs
Makeup1%ofthetotalbloodvolume
Can
leave
capillaries
via
ameboid
movement
and
move
through
tissue
spaces
TwofunctionsofWBCs
Protectthebodyagainstinvadingmicroorganisms
Removedeadcellsanddebrisfromtissuesbyphagocytosis
Namedaccordingtotheirappearanceinstainedpreparations
Granulocytes: containlargecytoplasmicgranules
Agranulocytes: verysmallgranulesthatcannotbeeasilyseenwiththelightmicroscope
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Granulocytes Neutrophils,Eosinophils,andBasophils
Containcytoplasmicgranulesthatstainspecifically(acidic,basic,orboth)withWrightsstain
ArelargerandusuallyshorterlivedthanRBCs
Havelobednuclei
Areallphagocyticcells
Neutrophils NeutrophilsmostcommontypeofWBC
Aremultinucleate
Havetwotypesofgranulesthat:
Takeupbothacidicandbasicdyes
Givethecytoplasmalilaccolor
Containperoxidases,hydrolyticenzymes,
anddefensins(antibioticlikeproteins)
Neutrophilsareourbodysbacteriaslayers
Pusisanaccumulationofdeadneutrophils,bacteria,celldebrisandfluidatsitesofinfections
Eosinophils Eosinophilsaccountfor14%ofWBCs
Haveredstaining,bilobednucleiconnectedviaabroadbandofnuclearmaterial
Haveredtocrimson(acidophilic)large,coarse,lysosomelikegranules
Lessentheseverityofallergiesbyreducinginflammation
Leadthebodyscounterattackagainstparasiticworms
Basophils Basophilsaccountfor0.5%ofWBCs
Havelarge,purplishblack(basophilic)granulesthatcontain
Histamine: inflammatorychemicalthatactsasavasodilatorandattractsotherWBCs(antihistamines
counterthiseffect)
Heparin: preventstheformationofclots
Agranulocytes Lymphocytesandmonocytes
Lackvisiblecytoplasmicgranules
Aresimilarstructurally,butarefunctionallydistinctandunrelatedcelltypes
Havespherical(lymphocytes)orkidneyshaped(monocytes)nuclei
Lymphocytes
Lymphocytesaccountfor25%ormoreofWBCs
Have
large,
dark
purple,
circular
nuclei
with
a
thin
rim
of
blue
cytoplasm
Arefoundbothinlymphoidtissuesandintheblood
Therearetwotypesoflymphocytes:TcellsandBcells
Bcells
Stimulatedbybacteriaortoxins
Giverisetoplasmacells,whichproduceantibodies
Foundprimarilyinblood
Tcells
Protectagainstvirusesandotherintracellularmicroorganisms
Attackanddestroythecellsthatareinfected
Foundprimarilyintissuesandlymph
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Monocytes
Monocytesaccountfor48%ofleukocytes
Theyarethelargestleukocytes
Theyhaveanabundantpalebluecytoplasm
Theyhavepurplestaining,U orkidneyshapednuclei
Theyleavethecirculation,entertissue,anddifferentiateintomacrophages
Arehighlymobileandactivelyphagocytic
Activatelymphocytestomountanimmuneresponse
LeukocyteDisorders Leukopenia
AbnormallylowWBCcountdruginduced
Leukemias
CancerousconditionsinvolvingWBCs
NamedaccordingtotheabnormalWBCcloneinvolved
Myelocyticleukemiainvolvesmyeloblasts
Lymphocyticleukemiainvolveslymphocytes
Acuteleukemiainvolvesblasttypecellsandprimarilyaffectschildren
Chronicleukemiaismoreprevalentinolderpeople
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Platelets Fragmentsofmegakaryocyteswithabluestainingouterregionandapurplegranularcenter
Functioninclottingbytwomechanisms
Formationofplateletplugs,whichsealholesinsmallvessels
Formationofclots,whichhelpsealofflargerwoundsinthevessels
TheirgranulescontainADPandthromboxanes
BloodPartIIBloodClottingandCoagulationHemostasisBloodClotting ThreeSteps
Vascularspasm
Plateletplugformation
Coagulation(bloodclotting)
VascularSpasm Vasoconstrictionofdamagedbloodvessel
Triggers
Directinjury
Chemicalsreleasedbyendothelialcellsandplatelets
Painreflexes
PlateletPlugFormation Positivefeedbackcycle
Atsiteofbloodvesselinjury,platelets
Sticktoexposedcollagenfiberswiththehelpofvon
Willebrandfactor,aplasmaprotein
Swell,becomespikedandsticky,andreleasechemical
messengers
ADPcausesmoreplateletstostickandreleasetheir
contents
SerotoninandthromboxaneA2enhancevascularspasm
and
more
platelet
aggregation
Coagulation Asetofreactionsinwhichbloodistransformedfromaliquidto a
gel
Reinforcestheplateletplugwithfibrinthreads
Threephasesofcoagulation
Prothrombinactivatorisformed(intrinsicandextrinsic
pathways)
Prothrombinisconvertedintothrombin
Thrombincatalyzesthejoiningoffibrinogentoformafibrin
mesh
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Phase1:PathwaytoProthrombinActivator Initiatedbyeithertheintrinsicorextrinsicpathway
(usuallyboth)
Triggeredbytissuedamagingevents
Involvesaseriesofprocoagulants
EachpathwaycascadestowardfactorX
Intrinsicpathway
Istriggeredbynegativelychargedsurfaces
(activatedplatelets,collagen,glass) Usesfactorspresentwithintheblood(intrinsic)
Extrinsicpathway
Istriggeredbyexposuretotissuefactor(TF)or
factorIII(anextrinsicfactor)
Bypassesseveralstepsoftheintrinsicpathway,
soisfaster
CoagulationPhase2:PathwaytoThrombin Prothrombinactivatorcatalyzesthetransformationof
prothrombintotheactiveenzymethrombin
Coagulation
CoagulationPhase3:PathwaytoFibrinMesh Thrombinconvertssolublefibrinogenintofibrin
Fibrinstrandsformthestructuralbasisofaclot
Fibrincausesplasmatobecomeagelliketrapforformed
elements
Thrombin(withCa2+)activatesfactorXIIIwhich:
Crosslinksfibrin
Strengthensandstabilizestheclot
ClotRetractionandRepair ClotRetraction
Actinandmyosininplateletscontractwithin3060minutes
Plateletspullonthefibrinstrands,squeezingserumfromtheclot
ClotRepair
Plateletderivedgrowthfactor(PDGF)stimulatesdivisionofsmooth
musclecellsandfibroblaststorebuildbloodvesselwall
Vascularendothelialgrowthfactor(VEGF)stimulatesendothelialcellsto
multiplyandrestoretheendotheliallining
Disordersof
Hemostasis
Thromboembolyticdisorders:undesirableclotformation
Bleedingdisorders:abnormalitiesthatpreventnormalclotformation
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ThromboembolyticConditions Thrombus:clotthatdevelopsandpersistsinan
unbrokenbloodvessel
Mayblockcirculation,leadingtotissuedeath
Embolus:athrombusfreelyfloatingintheblood
stream
Pulmonaryemboliimpairtheabilityofthe
bodytoobtainoxygen
Cerebralembolicancausestrokes Preventedby
Aspirin
Antiprostaglandinthatinhibits
thromboxaneA2
Heparin
Anticoagulantusedclinicallyforpre and
postoperativecardiaccare
Warfarin
Usedforthosepronetoatrialfibrillation
BleedingDisorders Thrombocytopenia:deficientnumberofcirculating
platelets
Petechiaeappearduetospontaneous,
widespreadhemorrhage
Duetosuppressionordestructionofbone
marrow(e.g.,malignancy,radiation)
Plateletcount
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Blood type Antigens Present Antibodies Present
A B Anti-A Anti-B
AB + +
B + +
A + +
O + +
ABOBloodGroup TheABObloodgroupsconsistsof:
Twoantigens(AandB)onthesurfaceoftheRBCs
Twoantibodiesintheplasma(antiAandantiB)
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RhBloodGroup RhpositivebloodhascertainRhantigens(theDantigen),whereasRhnegativeblooddoesnot
AntibodiesagainsttheRhantigenareproducedwhenaRhnegativepersonisexposedtoRhpositiveblood
TheRhbloodgroupisresponsibleforhemolyticdiseaseofthenewborn,whichcanoccurwhenthefetusisRh
positiveandthemotherisRhnegative
DiagnosticBloodTests Laboratoryexaminationofbloodcanassessanindividualsstateofhealth
Microscopicexamination:
VariationsinsizeandshapeofRBCs: predictionofanemia
TypeandnumberofWBCs: diagnosticofvariousdiseases
Chemicalanalysiscanprovideacomprehensivepictureofonesgeneralhealthstatusinrelationtonormalvalues
DiagnosticBloodTests Redbloodcellcount(million/mL)
Male4.66.2million/mL
Female4.25.4million/mL
Hemoglobinmeasurement(gramsofhemoglobinper/mLofblood
Male1418g/100mL
Female1216g/100mL
Hematocritmeasurement(percentvolumeofRBCs)
Male40%52%
Female38%48%
Whitebloodcellcount(WBCs/mL)
MaleandFemale50009000WBCs/mL
Differentialwhitebloodcellcount(thepercentageofeachtypeofWBC)
Neutorphils60%70%
Lymphocytes20%25%
Monocytes3%8%
Eosinophils2%4%
Basophils0.5%1%
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DiagnosticBloodTests Clotting
Plateletcountandprothrombintimemeasuretheabilityofthebloodtoclot
BloodChemistry
Thecompositionofmaterialsdissolvedorsuspendedinplasmacanbeusedtoassessthefunctioningand
statusofthebodyssystems
Glucose
Urea
Nitrogen Bilirubin
Cholesterol
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