Download 2.2 Notes #1

Topic2.2
Structure&FunctionoftheCardiovascularSystem
2.2.1
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ExercisePhysiology
Statethecompositionofblood
Bloodisheavierandmoreviscousthanwaterandaccountsfor
about8%ofourtotalbodyweight.
Healthyadultmaleshavearound5-6litersofbloodandfemales
about4-5liters.
Itscolorvaries,dependingupontheamountofoxygenitis
carrying,fromdarkred(oxygenpoor)tobrightred(oxygenrich).
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Erythrocytes(RedBloodCellsRBC’s)
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Leukocytes(WhiteBloodCells)
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Platelets(Thrombocytes)
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Plasma:liquidportionofbloodandresponsibleforthe
transportofelectrolytes,proteins,gases,nutrients,waste
productsandhormones.
Thetotalvolumeoferythrocytesisknownatthehematocrit!
2.2.2
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Distinguishbetweenthefunctionserythrocytes,leucocytesandplatelets
Erythrocytes(RedBloodCells):containanoxygen-carryingpigmentcalled
hemoglobin,whichcarriesoxygengivesblooditsredcolor.
o Thecellsliveforaround120days,andarereplacedatthe
astonishingrateof2millioncellspersecond.
Leukocytes(WhiteBloodCells):existinourbodiestocombatinfection
andinflammation.
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Theydothisbyingestingforeignmicrobesinaprocesscalled
phagocytosis.
Platelets(Thrombocytes):involvedintheprocessofclottingand
helprepairslightlydamagedbloodvessels.
PG37-47
Bloodperformsanumberofspecializedfunctions:
• Transportsnutrients,oxygen,carbondioxide,wasteproductsandhormonestocellsandorgansaroundthe
body.
• Protectsusfrombleedingtodeath-viaclotting,fromdisease,bydestroyinginvasivemicro-organismsandtoxic
substances.
• Actsasaregulatoroftemperature,thewater
contentincells,andbodypH.(rememberthat
narrowwindowwelike!!)
• Small%ofoxygendissolvesinplasma,mostofit
attachestoiron-richhemoglobin
o LungshavehighpartialpressureofO2so
O2easilybindstohemoglobin
o Activemuscleshavealowpartialpressure
soO2detachesfromhemoglobineasily
anddiffusesin.
• CO2isproducedduringexerciseandistransported
tothelungsviatheveins,partlydissolvedinblood
butmostlyinthetemporaryformofbicarbonate
Theeffectofexerciseandaltitudeontheamountofredbloodcells
• Hemoglobinconcentrationsarecontrolledbythehormoneerythropoietin(EPO)
o Stimulatesredbloodcellproduction
o Moreredbloodcells(RBC’s)=moreoxygen=increasedaerobicperformance
o Thisiswhyenduranceathletesliveathighaltitudes
§ LessoxygeninairstimulatesEPOtoproduce
moreRBC’sandthushemoglobin
§ Theyreturntosealevelandperformbetter
• ThereareillegalmethodstoincreasingRBC’sinathletes
o Blooddoping-removingsomebloodfromanathlete
aftertrainingataltitudewhichstimulatesEPOto
increaseRBC’s
o Thisbloodisreintroducedtotheathletejustbefore
competitiontoincreaseathleticperformance
• AthletescanbeinjectedwithsyntheticEPOsoskiptheabove
process.
• DetectionofsyntheticEPOandblooddopingishard
• Whenyoutraveltohighelevations(evenwithouttraining)your
EPOincreasesyouRBC’s
2.2.3Describetheanatomyoftheheartwithreferencetotheheartchambers,valvesandmajorbloodvessels
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Yourheartisaboutthesamesizeasyourfist.
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Anaverageadultbodycontainsaboutfivelitersofblood.
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Allthebloodvesselsinthebodyjoinedendtoendwouldstretch62,000milesortwoandahalftimesaround
theearth.
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Theheartcirculatesthebody'sbloodsupplyabout1,000timeseachday.
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Theheartpumpstheequivalentof5,000to6,000litersofbloodeachday.
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Arteries
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Relativelylargebloodvesselsindiameter
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Thickmuscularwallswithconsiderablepressure
exertedbytheoxygen-richbloodwithin
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Responsibleforbloodtransportawayfromthe
heart
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Arteriesbranchintonarrowerarterioles
Capillaries
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Bloodsuppliedbythearterioles
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Narrowbloodvesselswithextremelythinwalls
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Formextensivebranchingnetworkthroughtissues
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Sitesofgasexchangebetweenbloodandtissues
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Veins
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Capillarieslinktolargervesselscalledvenulesandthentolargerveins
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Deliversdeoxygenated(lowoxygencontent)backtowardstheheart
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Significantlylessmuscularandfibrousthanarteriesduetolowerinternalpressure
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Containsseriesofvalvesinordertopreventbackflow
Theheart
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Theinvoluntarypump(muscle)atthecenterofthe
cardiovascularsystem
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Itisasequenceofchambersthatareenclosedbywallsof
specializedmusclefibers(cardiacmusclecells!!)
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Smooth,striated,involuntary
Theheartisthelinkbetweentwodistinctloopsof
circulationinourbodies.
1. Pulmonarycirculationistheportionofthecardiovascularsystemwhichcarriesoxygen-depletedbloodawayfrom
theheart,tothelungs,andreturnsoxygenatedbloodbacktotheheart.
• Thetermiscontrastedwithsystemiccirculation.
2. Systemiccirculationistheportionofthecardiovascularsystemwhichcarriesoxygenatedbloodawayfromthe
heart,tothebody,andreturnsdeoxygenatedbloodbacktotheheart.
• Thistermiscontrastedwithpulmonarycirculation.
SystemicCirculation
PulmonaryCirculation