Handouts Blood F11

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

Documents

Handouts Blood F11