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BIO 202 > CV Study Guide > Flashcards

CV Study Guide Flashcards

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1
Q

Thecardiovascularsystemconsistsofthe

A

heartandallthebloodvessels.Functionally,

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2
Q

theheartislikea

A

doublepumpwitheachpumpconnectedtotheotherthroughalongseriesofbloodvessels

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3
Q

heart consists of how many chambers

A

4

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4
Q

tworeceivingchamberscalled

A

atria

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5
Q

twopumpingchamberscalled

A

ventricles.

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6
Q

Theleftsideoftheheartalwayspumps

A

oxygenatedblood,

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7
Q

andtherightsidealwayspumps

A

deoxygenatedblood.

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8
Q

Thepulmonarycircuitrefersto

A

allthebloodvesselsthattakedeoxygenatedbloodfromtherightventricleofthehearttothelungs,andthenreturnoxygenatedbloodtotheleftatrium.

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9
Q

systemiccircuit.

A

bloodvesselsthattransportthisoxygenatedbloodtothebody

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10
Q

gasexchangeoccurswithin

A

capillaries

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11
Q

capillaries

A

microscopicbloodvesselsonlyonecelllayerthick

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12
Q

capillaries wall made up of

A

simplesquamousepithelium.

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13
Q

Theseflatcellseasilypermitthediffusionofgases,suchasoxygen(O2)andcarbondioxide(CO2)

A

simplesquamousepithelium.

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14
Q

normalby-productofcellularrespirationandgraduallybuildsupwithinbodycells

A

Carbondioxide

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15
Q

Carbondioxidediffusesfromthebodycellsintothe

A

capillary.

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16
Q

pathwaythatbeginsandendswiththe

A

right atrium

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17
Q

whichatrioventricularvalve—bicuspidortricuspid—comesfirst

A

Yourideyourtricycle(tricuspid)beforeyourbicycle(bicuspid).

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18
Q

Coronarycirculationreferstothe

A

bloodsupplytotheheart

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19
Q

oronaryarteriessupplyoxygenatedbloodtothe

A

heart

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20
Q

cardiacveinscarrydeoxygenatedbloodbackto

A

the heart

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21
Q

flowchartsummarizescoronarycirculationthroughthebloodvessels

A

Baseofaortaleftandrightcoronaryarteriesbranchesofcoronaryarteries(circumflexa.,anteriorinterventriculara.,marginala.,posteriorinterventriculara.)coronarycapillariescardiacveinscoronarysinusrightatrium

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22
Q

coronaryarteriesbecomeblocked

A

bloodsupplytotheheartisreduced

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23
Q

coronaryarteriesbecomeblocked deprives cardiac muscles cells of

A

oxygen

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24
Q

if coronary arteries remain blocked for many years, it can lead to

A

myocardialinfarction(heartattack)

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25
Q

Todistinguishtheanteriorfromtheposteriorviewoftheheart

A

usethecoronarysinusasalandmarkfortheposteriorview

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26
Q

Goodlandmarksfortheanteriorviewinclude

A

pulmonarytrunk,anteriorinterventricularartery,circumflexartery,andascendingaorta.

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27
Q

heartisdividedinto

A

leftandrighthalvesandhasfourchambers,twoatriaandtwoventricles.

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28
Q

firstchamberstoreceivebloodfromthebody.

A

atria

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29
Q

what happens in the atria

A

fillwithblood,contract,andtransferbloodtothepumpingchambers,orventricles

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30
Q

which are the pumping chambers

A

ventricles.

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31
Q

rightventriclepumps

A

deoxygenatedbloodtothelungs

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32
Q

leftventriclepumps

A

oxygenatedbloodtotherestofthebody

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33
Q

hearthastwodifferenttypesofvalves

A

atrioventricular(AV)valvesandsemilunarvalves

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34
Q

atrioventricular(AV)valvesandsemilunarvalves.

A

TheAVvalvesarelocatedbetweentheatriaandtheventricles.Theoneontherightsideofthehearthasthreevalveflaps,soitiscalledthetricuspidvalve,andtheoneontheleftsidehastwovalveflaps,soitiscalledthebicuspid(mitral)valve.Thesevalvespermitaone-wayflowofbloodfromatriatoventricles.

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35
Q

semilnar valves

A

??

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36
Q

chordaetendineae

A

Long,fibrous,cord-likestructures anchor the valve flaps to the papillary muscles

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37
Q

papillary muscles

A

long,cone-shaped,muscularextensionsoftheinnerventricles

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38
Q

chordaetendineaeandpapillarymuscleshelp

A

keeptheAVvalvesclosedduringventricularcontraction.

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39
Q

semilunarvalvesarelocatedat

A

thebaseofeachmajorarterythatleaveseachventricle

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40
Q

Ontherightsideisthepulmonarysemilunarvalve,andontheleftistheaorticsemilunarvalve

A

??

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41
Q

Semilunarvalvesprevent

A

backflowofbloodintotheventricles

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42
Q

Fromoutermosttoinnermost,thewalloftheheartismadeofthreelayers

A

epicardium,myocardium,andendocardium

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43
Q

Theepicardium(visceralpericardium)ismadeof

A

fibrousconnectivetissueandistheinnermostlayerofthepericardialsacthatsurroundstheheart

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44
Q

myocardiumiscomposedof

A

multiplelayersofcardiacmuscleandmanybloodvesselsandnerves

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45
Q

endocardiumismadeof

A

simplesquamousepitheliumandlinestheinsideofalltheheartchambersandvalves

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46
Q

endocardium is continuous with the

A

endotheliumofbloodvesselsthatenterandexittheheart,suchastheaortaandthepulmonaryveins.

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47
Q

Thesemilunarvalvesresembleamodified

A

peacesignwhenclosed

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48
Q

Todistinguishbetweentheleftandrightventricles,notethatthewalloftheleftventricleis

A

thicker than the wall of the right ventricle

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49
Q

Theatrioventricularvalvesandassociatedstructuresresemblea

A

parachute; The valve flaps are the parachute, ventricle. the parachute cords are the chordae tendineae, and the paratrooper is the papillary muscle

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50
Q

Thehearthasitsowninternalregulationsystemtoachievetwoimportantfunctions:

A

(1)triggeringtheheartbeat,and(2)coordinatingthetimingbetweencontractionoftheatriaandcontractionoftheventricles

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51
Q

intrinsicconductionsystem

A

Thehearthasitsowninternalregulationsystemtoachievetwoimportantfunctions

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52
Q

without the intrinsicconductionsystem to ensure that the heart chambers do what

A

completelyfillwithbloodbeforecontracting,theheartwouldbeaveryinefficientpump

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53
Q

intrinsicconductionsystemconsistsofthefollowingsixstructures

A

sinoatrial (SA) node; Internodal pathway; atrioventricular node; atrioventricular (AV) bundle; bundle branches (right and left); purkinje fibers

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54
Q

intinsic conduction system cann be structurally divided into two main parts

A

thenodes(SAandAVnodes)andthepathway(internodalpathway,AVbundle,bundlebranches,andPurkinjefibers).

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55
Q

the nodes

A

(SAandAVnodes)

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56
Q

the pathway

A

(internodalpathway,AVbundle,bundlebranches,andPurkinjefibers)

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57
Q

Thenodesconsistof

A

clustersofspecializedcardiacmusclecellsthatcontainveryfewcontractileproteins—myosinandactin—foundinnormalcardiacmusclecells

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58
Q

nodes are the only cells in the body that are

A

autorhythmicmusclecells

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59
Q

Insteadofcontracting,nodesserveasakindof

A

“sparkplug,”orstimulus,toestablishtheheartbeat

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60
Q

SAnodeislocated

A

withinthewalloftherightatriumandisreferredtoastheprimarypacemaker.

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61
Q

AVnodeislocatedinthe

A

septumbetweenthetwoatriaandisreferredtoasthesecondarypacemaker

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62
Q

Likesmoothmusclecells,cardiacmusclecellscan

A

stimulateadjacentcells.

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63
Q

becausecardiacmusclecellsinterdigitatewitheachotherlikepiecesofajigsawpuzzle,stimulatingthefirstcellwill

A

quicklystimulatealltheothersinthepathway.

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64
Q

Theinternodalpathwayradiatesfromthe

A

SAnodeandextendstotheleftandrightatriaandAVnode.

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65
Q

AVbundleisarelativelyshortsegmentofcellsthatextendsfrom

A

theAVnodeandpenetratesintothetopoftheinterventricularseptum

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66
Q

AV BUNDLE IS THE ONLY

A

electricalconnectionbetweentheatriaandtheventricles.

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67
Q

AV bundle splits into two pathways at the interventricular septum

A

therightandleftbundlebranches,whichextendthroughtheinterventricularseptumtowardtheapexoftheheart

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68
Q

Theflowoftheimpulseforcontractionalwaysmovesinthefollowingsequence:

A

SAnodeinternodalpathwayAVnodeAVbundlebundlebranchesPurkinjefibers

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69
Q

theautorhythmiccellswithintheSAnodetriggerthe

A

impulsetospreadtotheleftandrightatriathroughtheinternodalpathway.

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70
Q

Theimpulsecausesthe_____tocontract,whichforcesbloodintotheventricles.

A

atria

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71
Q

Adelayinventricularcontractionisneededtoallow

A

theventriclestofillwithblood.ThisdelaycomesintheformofthetimeittakestostimulatetheAVnodeandsendtheimpulsedowntheAVbundleandbundlebranches.BythetimetheimpulsehasspreadtothePurkinjefibers,theventricleshavefinishedfillingwithblood,andtheventriclesarestimulatedtocontract.

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72
Q

Theintrinsicconductionsystemisan___________thatleadstothecontractingoftheheartchambers,amechanicaleventImpulsePathwaySpecializedcardiac

A

ELECTRICALEVENT

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73
Q

Anelectrocardiogram(ECGorEKG)

A

graphoftheheart’selectricalactivityasexpressedinmillivolts(mV)overtime.

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74
Q

instrumentusedtoobtainanECGiscalledan

A

electrocardiograph

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75
Q

AnECGisusedtodetectif

A

electricalconductionpathwaywithintheheartisnormalandifanydamagehasbeendonetotheheart

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76
Q

InatypicalleadIIrecording,threedifferentwavesappear:

A

P,QRScomplex,andT; Each wave represents an electrical event called a depolarization or a repolarization.

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77
Q

electricaleventsstimulate

A

cardiacmusclewithintheheartwalltoeithercontractorrelax.Consequently,theseeventsleadtothecontractionandrelaxationoftheheartchambers—atriaandventricles.

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78
Q

P WAVE

A

atrialdepolarization—attheendofthePwave,bothatriahavedepolarized,whichcausestheatriatocontract.

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79
Q

QRS COMPLEX

A

ventriculardepolarization—attheendoftheQRScomplex,bothventricleshavedepolarized,whichcausestheventriclestocontract.Note:Atrialrepolarizationalsooccursduringthisperiod,butitismaskedbytheventriculardepolarization.

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80
Q

T WAVES

A

ventricularrepolarization—attheendoftheTwave,bothventricleshaverepolarized,whichcausestheventriclestorelax.

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81
Q

Twotypesofvariations IN AN ECGmaysignalabnormalities:

A

Variationinwaveheight(theymaybeelevatedordepressed); 2.Variationinnormaltimeintervals

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82
Q

ifaPwaveiselevated,itmayindicate

A

atrialenlargement.

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83
Q

IftheQRScomplexiselevated,itmayindicate

A

ventricularenlargement.

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84
Q

AtallandpointedTwavemayindicate

A

myocardialischemia.

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85
Q

Theheartisessentially

A

twopumpsthatworktogetherasonesynchronizedunit.

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86
Q

Theleftsidepumpsonly

A

oxygenatedblood,andtherightsidepumpsonlydeoxygenatedblood

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87
Q

Thecardiaccyclereferstoallthe

A

pumpingactionsthatoccurwithintheheartduringoneentireheartbeat.Itconsistsofboththeatriaandtheventriclesfillingwithbloodandthencontracting.Itbeginswithcontractionoftheatriaandendswithrefillingoftheatria.Onaverage,thiscontinuouscycletakesabout800msec.tocompleteinanadult.

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88
Q

Theatriaandtheventricleshaverepeatedpatternsofcontraction_____andrelaxation________.

A

SYSTOLE AND DIASTOLE

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89
Q

Theatriafunctionasthe

A

receivingchambersofbloodfromthebody.Aftertheyfillwithblood,theycontractandforceblooddownwardintothetruepumps—themorepowerfulventricles.

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90
Q

TRUE PUMPS OF THE HEART

A

THE VENTRICLES

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91
Q

Becausethesechambershavethemoredifficulttaskofpumpingthebloodtothebody,theyhaveathickerlayerofcardiacmuscleintheirwallsandalargervolume.

A

THE VENTRICLES

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92
Q

Recallthatthehearthastwopairsof

A

valves:atrioventricular(AV)valvesandsemilunarvalves.

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93
Q

TheAVvalvesfunctionas

A

one-wayvalvestopermitbloodtoflowfromtheatriatotheventricles.Theclosingofthesemilunarvalvespreventsbloodfromflowingbackintotheventriclesafterbeingejected.

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94
Q

Theelectrocardiogram(ECG)isrelatedtothe

A

cardiaccycle.

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95
Q

AnECGmeasures

A

atrial contraciton; sovolumetric ventricular contraction ; Ventricular ejection; Isovolumetric ventricular relaxation; Passive ventricular filling

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96
Q

,thecardiaccyclehasbeendividedintofivesteps,asfollows:

A

atrial contraciton; sovolumetric ventricular contraction ; Ventricular ejection; Isovolumetric ventricular relaxation; Passive ventricular filling

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97
Q

atrial contraciton;

A

ECGconnection:fromPwavetoQwave; AVvalvesopen; Semilunarvalvesclosed; Description:Theleftandrightatriacontractsimultaneously,causingtheatrialpressuretoincrease.ThisforcesbloodthroughtheAVvalvesandintotheventricles.Theventriclesarerelaxedandfillingwithblood.Thesemilunarvalvesareclosedbecausethepressureintheventriclesistoolowtoforcethemopen.

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98
Q

sovolumetric ventricular contraction ;

A

ECGconnection:beginswithRwave●AVvalvesclosed; Semilunarvalvesclosed●Description:Theventriclesbegincontractinginthisphase,causingtheventricularpressuretoincrease.HigherventricularpressurerelativetotheatriaclosestheAVvalves.Thevolumeofbloodintheventriclesremainsconstant(isovolumetric).Allheartvalvesareclosed.

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99
Q

Ventricular ejection;

A

ECGconnection:fromSwavetoTwave●AVvalvesclosed●Semilunarvalvesopen●Description:Theventriclescontinuecontractingduringthisphase.Likewringingoutawetrag,theventricleswringtheblood out, beginning at the apex and moving upward. This allows for the maximum volume of blood to be ejected - about 70ml per ventricle. The high ventricular pressure forces the semilunar valves to open, and blood is ejected into the pulmonary arteries and the aorta

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100
Q

Isovolumetric ventricular relaxation;

A

ECGconnection:beginsatendofTwave●AVvalvesclosed●Semilunarvalvesclosed●Description:Theventriclesarerelaxing,andtheheartvalvesareallclosed.Thevolumeofbloodintheventriclesremainsconstant(isovolumetric).Becauseventricularpressuresarehigherthanatrialpressures,nobloodflowsintotheventricles.Ventricularpressureisquicklydecreasingduringthisphase.

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101
Q

Passive ventricular filling

A

ECGconnection:afterTwavetonextPwave; ●AVvalvesopen●Semilunarvalvesclosed; ●Description:Asbloodflowsintotheatria,theatrialpressureincreasesuntilitexceedstheventricularpressure.ThisforcestheAVvalvesopen,andbloodfillstheventricles.Thisisthemainwaytheventriclesarefilled.Attheendofthisphase,theventricleswillbeabout70–80%filled.

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102
Q

TheCARDIACCYCLEisa

A

MECHANICALEVENTlikesqueezingabottleofwater.Justasthepressureinthebottleriseswhensqueezed,sodoesthepressureinaheartchamberwhenitiscontracted.

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103
Q

Inthecentralnervoussystem(CNS),thecardiovascular(CV)centerinthemedullaoblongatais

A

thecommand-and-controlcenterforregulatingheartfunction.Itusesreflexpathwaystocontrolheartrate.

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104
Q

ThethreemajorperipheralsensoryreceptorsthatprovideinputtotheCVcenterare:

A

1.Proprioceptors; 2.Chemoreceptors—; 3.Baroreceptors;

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105
Q

1.Proprioceptors—

A

measuretensionchangesinmusclesandjoints

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106
Q

2.Chemoreceptors—

A

detectchangesinbloodaciditybysensingchangesinCO2andHlevels

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107
Q

3.Baroreceptors—

A

locatedinthecarotidsinus,aorticarch,andotherarteries;detectchangesinbloodpressure

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108
Q

TheCVcentersendsitsmotoroutputtotheheartthroughtwodifferentnerves:

A

1.Vagusnerve—todecreaseheartrate; 2.Cardiacacceleratornerve—toincreaseheartrate

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109
Q

VAGUS NERVE

A

TO DECREASE HEART RATE

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110
Q

CARDIAC ACCELERATOR NERVE

A

TO INCREASE HEART RATE

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111
Q

Theinternalpacemakerswithintheheart—

A

theSAnodeandAVnode—

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112
Q

Theinternalpacemakerswithintheheart helps set the

A

itsnormalrateandrhythm

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113
Q

Thevagusnerve(cranialnerveX)ispartofthe

A

parasympatheticdivisionoftheANSandsendsimpulses to the heart to decrease heart rate

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114
Q

why is the vagus nerve a mixed nerve

A

meaningthatitcontainsbothsensoryandmotorneurons.Baroreceptors,locatedinthecarotidsinus,aorticarch,andotherarteries,detectchangesinbloodpressure

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115
Q

Asbloodpressureincreasesabovenormallevels,impulsesaresentalongsensoryneuronstothe

A

CVcenterandthencarriedalongmotorneuronswithinthevagusnervetotheheart.

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116
Q

Thevagusnerveinnervatestheheartatthe

A

SAnodeandAVnode.

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117
Q

THE VAGUS NERVE FUNCTIONS TO INHIBIT THE HEART, THEREBY ….

A

reducingtheheartrateandstrengthofcontractions.This,inturn,decreasescardiacoutput,whichlowersbloodpressurebacktonormal.Atthesametime,impulsesalsoaresentoutalongvasomotornerves(notshowninillustration)thatstimulatevasodilation,therebyfurtherloweringthebloodpressure.

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118
Q

Thecardiacacceleratornerveispartofthe

A

sympatheticdivisionoftheANSandsendsimpulsestothehearttoincreasetheheartrate.

119
Q

Asbloodpressuredecreasesbelownormallevels,thisisdetectedby

A

baroreceptorsthatsendimpulsesalonganeuralnetworkovertotheCVcenter,thentothespinalcordandtotheheart.Thefinalnerveinthispathway—thecardiacacceleratornerve—

120
Q

thecardiacacceleratornerve—innervatestheheartatthe

A

SAnode,AVnode,andcardiacmuscleintheventricularwall(ventricularmyocardium).Theresponseisthatboththeheartrateandstrengthofcontractionsincrease.This,inturn,increasescardiacoutput,whichincreasesbloodpressure.Atthesametime,impulsesaresentoutalongvasomotornerves(notshowninillustration)thatstimulatevasoconstrictionandtherebyfurtherincreasebloodpressure.

121
Q

Thebodyhasfivefundamentaltypesofbloodvessels:

A

arteries,arterioles,capillaries,venules,andveins.Allofthemconnectinthefollowingpredictablepattern:

122
Q

PATH OF BLOOD

A

Heart TO artery(larger) TO artery(smaller)TO arterioleTO capillary TOvenuleTO vein(smaller)TO vein(larger)

123
Q

Arteriesalwayscarryblood

A

awayfromtheheart.

124
Q

ARTERIES ARE THICKER WALLED THAN VEINS BECAUSE

A

becausethebloodwithinthemisatahigherpressure.

125
Q

Allveinsalwayscarryblood

A

BACK TO THE HEART

126
Q

WHY ARE VEINS THINNER WALLED

A

BECAUSE PRESSURE WITHIN THEM IS LOWER

127
Q

LARGER VEINS CONTAIN

A

valves—similartoonewaysemilunarvalvesintheheart—thatassistthelow-pressurevenousbloodreturntotheheart.

128
Q

Whenapersonisstanding,gravityworksagainst

A

venousbloodflow.

129
Q

valvesbreakuplargerveinsinto

A

smallersegments.

130
Q

Arteriesandveinsconnectatthemicroscopiclevelby

A

capillarynetworks.

131
Q

Capillariesare

A

thesmallestbloodvesselsinthebodyandareimportantfunctionallybecausegasandfluidexchangeoccurshere.Theirentirewallisoftenasinglecelllayerinthickness.

132
Q

Arteriolesandvenulesaremicroscopicvesselsthatfeedanddrain

A

Capillaries

133
Q

ATERIOLOES ANDcapillariesarestructurallysimilartoacapillaryexcept

A

theyhavesmallamountsofsmoothmusclearoundthem.Thesmoothmusclearoundanarteriolecanbestimulatedtoeitherconstrict(vasoconstriction)orrelax(vasodilation).This,inturn,causeschangesinbloodflowtoacapillaryandsystemicbloodpressure.

134
Q

Vasoconstrictionofarterioles

A

decreasesbloodflowandincreasesbloodpressure,andvasodilationdoesjusttheopposite.

135
Q

Arteriesandveinshavethreemajorlayersintheirwalls:

A

tunicaexterna,tunicamedia,andtunicainterna:

136
Q

tunicaexterna,

A

connectivetissuelayermademostlyofcollagenfibers

137
Q

tunicamedia,

A

layersofsmoothmuscleandsomeelasticfibers

138
Q

tunicainterna:

A

endotheliallayer(simplesquamousepithelium)withunderlyinglooseconnectivetissue

139
Q

somearteries/veinscarryoxygenatedbloodandotherscarrydeoxygenatedblood. TRUE OR FALSE

A

TRUE

140
Q

ArteriesAway!

A

Arteriesalwayscarrybloodawayfromtheheart.

141
Q

●Torecallonestructuraldifferencebetweenarteriesandveins:

A

VeinshaveValves(arteriesdonothavevalves).

142
Q

●Todistinguishanarteryfromaveinunderthemicroscope,

A

rememberthatarteriesalwayshaveathickertunicamedia.

143
Q

Bloodalwaysfollowsapredictablecircuitthroughbloodvessels.Therearefivefundamentaltypesofbloodvesselsinthebody:

A

arteries,arterioles,capillaries,venules,andveins.Allofthemconnectinthefollowingpattern:

144
Q

PATH OF BLOOD

A

HEART TO LARGE ARTERY TO SMALLER ARTERY TO ARTERIOLOE TO CAPILLARY TO VENULE TO SMALLER VEIN TO LARGER VEIN TO HEART

145
Q

AS ARTERIES MOVE FARTHER AWAY FROM THE HEART (DISTANCE INCREASES) WHAT HAPPENS TO BLOOD PRESSURE

A

Asdistancefromtheheartincreases,bloodpressuredecreases.

146
Q

Arteriesandveinsconnecttogetheratthemicroscopiclevelby

A

capillarynetworks.

147
Q

Capillariesarethesmallest

A

bloodvesselsinthebodyandare

148
Q

Capillariesveryimportantfunctionallybecause

A

gasexchangeandfluidexchangeoccurshere.Oxygenexitsthebloodtobeusedbybodycells,andcarbondioxideentersthebloodfromcells.Theliquidplasmaisfilteredoutofthebloodtobecomeinterstitialfluid(tissuefluid).

149
Q

VeinscarrY WHAT TO WHERE

A

low-pressure,deoxygenatedblooddrainintothevenacava,whichdrainsintotheheart’srightatrium(RA)

150
Q

WHAT IS THE RIGHT ATRIUM

A

receivingchamberfillswithblood,contracts,andforcesbloodintotherightventricle(RV).

151
Q

WHAT HAPPENS IN THE RIGHT VENTRICLE

A

Allthisdeoxygenatedbloodisthenpumpedoutoftherightventricletogotothelungstogetoxygenated.

152
Q

WHAT HAPPENS IN THE LUNGS

A

thepulmonarycapillariesfunctiononlyforgasexchange,inwhichoxygendiffusesintothebloodandcarbondioxidediffusesout.Theoxygenatedbloodisthentransportedthroughveinstotheleftatrium(LA)

153
Q

WHAT HAPPENS IN THE LEFT ATRIUM

A

LAfillswithblood,contracts,andforcesbloodintotheleftventricle(LV).

154
Q

WHAT HAPPENS IN THE LEFT VENTRICLE

A

hisoxygenatedbloodisthenpumpedouttothebodyviatheaorta.

155
Q

Theheartfeedsitsowncardiacmusclefirstthrough

A

coronarycapillariessoitcancontinuepumpingbloodeveryminuteofeveryday

156
Q

Arteriescarry

A

oxygenatedbloodabovethehearttothecapillariesinthebrain,trunk,andupperlimbs.Otherarteriescarrybloodbelowtheheart

157
Q

ARTERIES CARRY BLOOD BELOW THE HEART TO THE FOLLOWING MAJOR AREAS

A

Digestiveorgansandspleen; Kidney; Gonads; Liver, lower limbs

158
Q

WHAT HAPPENS AT THE Digestiveorgansandspleen—

A

Aftergasandfluidexchangeoccursatthesplenicandmesentericcapillaries,deoxygenatedbloodiscarriedbyveinstothehepaticportalsystemintheliver.Notethatcapillariesinthissystemarenotforthetypicalpurposeofgasandfluidexchange.Instead,thesehighlypermeablecapillariesarespecializedfordeliveringnutrientsabsorbedbythedigestivetracttolivercellsbeforeenteringthegeneralcirculation.Thelivercellsserveasspecialprocessingcentersthatperformmanyfunctions.Forexample,theystoreglucoseasglycogenanddetoxifyalcohols.

159
Q

WHAT HAPPENS AT THE KIDNEY

A

Anotheruniquegroupofpermeablecapillariesistheglomerularcapillaries.Likethecapillariesinthehepaticportalsystem,thesearealsonotforthetypicalpurposeofgasandfluidexchange.Instead,theyarespecializedtofilteronlythebloodplasma,placeitinaseparatetubularsystem,andprocessthisliquidintourine.Thesecapillariesleadintotheperitubularcapillaries,wheregasandfluidexchangedoesoccur.

160
Q

WHAT HAPPENS AT THE GONAD

A

Inthemale,gasandfluidexchangeoccursatcapillariesinthetestes,whereasinthefemale,thisoccursatcapillariesintheovaries.

161
Q

Thetwotypesofflowpatternsare:

A

(1)laminarflow,and(2)turbulentflow.

162
Q

1Laminar(lamina4layer)flowisthe

A

normalflowpatterninhealthybloodvessels; Theconcentriclayersoffluidflowtogether,butnotatthesamerate.Asshownintheillustration,theouterlayerstravelmoreslowlythantheinnerlayers.Why?Asthefluidintheoutermostlayerrubsagainstthevesselwall,itishinderedbytheforceoffrictionandmovestheslowest.Incontrast,thefluidinthecenterofthetubeisinterferedwiththeleast,soitmovesthefastest.Normal,healthybloodvesselsaresmoothontheirinnersurface.Likethesmoothsurfaceontheinsideofagardenhoseoradrainpipe,thisallowsthefluidtoflowthroughmosteasily.

163
Q

Asanotherclinicalexample,turbulentbloodflow

A

isheardmovingthroughadefectiveheartvalveasa“murmur.”

164
Q

2Turbulentflowistheresultofanydisruptioninthenormal,

A

laminarflow.

165
Q

Somelowlevelsofturbulentflowarenormal

A

asbloodflowsthroughallthevesselsinthebody,buthighlevelsmayindicateanabnormality.

166
Q

WhatcausesTURBULENCE?Twothings:

A

(1)physicalchangeinavessel(ex.:constriction,sharpturn,ornarrowingofavessel)or(2)Diseasestate(ex.:atherosclerosis).Becauselargebloodvesselsconnecttosmallerones,somenarrowingisnormal,butitisagradualchangethatdoesn’tusuallyresultinturbulentflow.

167
Q

(1)physicalchangeinavessel(ex.:

A

constriction,sharpturn,ornarrowingofavessel)or

168
Q

(2)Diseasestate(ex.:

A

atherosclerosis).Becauselargebloodvesselsconnecttosmallerones,somenarrowingisnormal,butitisagradualchangethatdoesn’tusuallyresultinturbulentflow.

169
Q

Theheartgeneratesthebloodpressureby

A

ejectingbloodintothearterialsystem.

170
Q

Bloodpressure(BP)isatypeof

A

hydrostaticpressure—orforceofafluidagainstthewallofatube.

171
Q

Astheventriclescontractandforcebloodoutintothearteries,thesevessels

A

expand,andthepressurerisestoamaximumpressure.Astheventriclesrelax,andnomorebloodisejectedintothearteries,thearteriesrecoil,andpressurefallstoaminimumpressure.

172
Q

thesourceofourpulse.

A

constantcycleofrisingandfallingbloodpressureis

173
Q

Whenbloodpressureistaken,itismeasuredin

A

mmHgandexpressednumericallyasthemaximumpressureovertheminimumpressure.Thisisreferredtoasthesystolicpressureoverthediastolicpressure.Forexample,anormalbloodpressurereadingmightbe120/70,readas“120over70.”

174
Q

Bloodpressurehastobehomeostaticallymaintainedatanormallevel.Ifbloodpressureexceedsnormallevels,itcancause

A

smallervesselstorupture,leadingtoanythingfromastrokeeventoblindness.

175
Q

IfBLOOD PRESSURE levelsfalltoolow,thisalsocanleadtonumerousproblems.Forexample,filtrationistotallydependentonpressure.

A

Thekidneysconstantlyfilterthebloodtoremovewasteproducts,andthecapillariesinallourorgansfilterthebloodtoformtissuefluid.Nopressure,nofiltration.ThebodyhasnumerousphysiologicalmechanismstoincreaseBPwhenitfallstoolow.

176
Q

bloodpressureresultsfrom

A

theforceofbloodagainstthewallofthebloodvessel.

177
Q

1Whenabloodpressurecuffiswrappedaroundtheupperarm,theintendedpurposeisto

A

compressthebrachialartery,whichdeliversoxygenatedbloodtothearm.

178
Q

Bloodpressure(BP)isatypeof

A

hydrostaticpressure(HP)orfluidforceagainstthewallofatube.

179
Q

Theheartgeneratesthebloodpressurebyejectingbloodinto

A

the arterial system

180
Q

themostmicroscopicbloodvesselsinthebody,joinarteriolestovenules

A

Capillaries,Theirdiameterissosmallthatredbloodcellsmustpassthroughsinglefile.Thesevesselsformaninterconnectingnetworkormeshofvesselscalledcapillarybeds.

181
Q

capillarybeds.

A

interconnectingnetworkormeshofvessels

182
Q

.Allthevarioustissuesinthebodydependonthesetoremovewastesandtodelivernutrientsandfluid.

A

capillarybeds.

183
Q

Thetubelikestructureofeachcapillaryissimple.Thewallofthevesselismadeupof

A

endothelialcellsorsimplesquamousepithelialcells.Eachofthesecellsisflattoallowforeasydiffusionofsolutesfrombloodtotissuecellsandviceversa.

184
Q

basementmembrane

A

Wrappedaroundtheoutsideofthesecellslikeathinblanketareproteinfiberscalledthebasementmembrane.

185
Q

intercellularclefts

A

Gapsbetweenadjacentendothelialcellscalledallowforpassageoffluidandsmallsolutes.

186
Q

Thethreetypesofcapillariesare:

A

(1)continuouscapillaries,(2)fenestratedcapillaries,and(3)sinusoidalcapillaries.

187
Q

(1)continuouscapillaries,

A

most common; least permeable; skin, connective tissues, skeletal muscle, smooth muscle and lungs

188
Q

(2)fenestratedcapillaries,

A

most permeable, found in kidneys, small intestines, choroid plexus in brain and some endocrine glands

189
Q

(3)sinusoidalcapillaries.

A

most permeable, found in liver, red bone marrow, spleen, and some endocrine glands

190
Q

fenestrations

A

endothelial cells contain small holes called fenestrations that increase permeability

191
Q

Bloodflowthroughacapillarybediscontrolledby

A

bandsofsmoothmusclecalledprecapillarysphincters.

192
Q

precapillarysphincters.

A

Whentheyareclosed,bloodbypassesthecapillarybedbygoingthroughtheshunt.Whentheyareopen,bloodmovesthroughtheentirecapillarybed(asillustrated).Thisallowsthebodytorespondtodifferentsituations.Forexample,duringexercise,thesphinctershavetobeopenedinthecapillariesinskeletalmusclestomeetthemuscle’sincreasedoxygendemandanddealwithincreasedproductionofcarbondioxide.Duringthedigestionofaheavymeal,morebloodhastobeshuntedtothecapillariesinthedigestivetractratherthantotheskeletalmuscles.

193
Q

Capillarybedsarethesitesof

A

nutrientandwasteexchangebetweenthebloodandbodycells.Nutrientsmovefromthebloodintotissuecells,andwastesmovefromtissuecellsintotheblood.Forexample,therespiratorygases—oxygenandcarbondioxide—diffuseacrossthewallofthecapillary.

194
Q

Oxygenisavitalnutrientthatdiffusesoutofthebloodandinto

A

tissuecells,andcarbondioxideisawasteproductthatdiffusesfromtissuecellsintotheblood.

195
Q

Recallthatdiffusiondependsona

A

gradient(seepp.78–79).Theruleforsimplediffusionisthatasolutemovesfromaregionofhighersoluteconcentrationtoaregionoflowersoluteconcentration.Oxygeniscarriedinthebloodprimarilybytheproteinhemoglobin.Ascellsconsumeoxygentometabolizeglucoseinthecellularrespirationprocess,thisensuresthatthegradientforoxygenismaintained.Carbondioxideisaby-productofcellularrespiration,soitmaintainsagradientasitconstantlyaccumulateswithinbodycells.

196
Q

Gasexchangeoccursacross

A

capillarybeds.

197
Q

Thisishowoxygenisdeliveredtoyourcellsandhowcarbondioxideisremovedfromtissues.

A

capillarybeds.

198
Q

Twoprocessesareoccurringsimultaneouslywithdiffusion:

A

filtrationandreabsorption.

199
Q

filtrationprocessiscompletelydependentona

A

force.NO FORCE, NO FILTRATION

200
Q

(CHP)

A

capillaryhydrostaticpressure

201
Q

capillaryhydrostaticpressure

A

thebloodpressureinsidethecapillarieS

202
Q

THIS drivesthefiltrationprocessandismeasuredinmillimetersofmercury(Hg).

A

capillaryhydrostaticpressure (CHP)

203
Q

Acrossacapillarybed,theCHPquicklydropsas

A

bloodmovesfromthehigherpressurearterioleend(35mmHg)tothelowerpressurevenuleend(18mmHg).

204
Q

WorkingagainsttheCHPisacounterforcecalledthe

A

bloodcolloidalosmoticpressure(BCOP).

205
Q

Osmoticpressurerepresents

A

theforcefromwater’stendencytomoveacrossasemipermeablemembranetowardthesolutionwiththegreaterconcentrationofnonpenetratingsolutes(primarilyproteins)

206
Q

osmoticpressureisproportionaltothe

A

soluteconcentration.Thehigherthesoluteconcentration,thegreateristheosmoticforce.

207
Q

Becausetheconcentrationofnonpenetratingsolutesinthebloodisgreaterthanthetissuefluidwithintheinterstitialspaces,water’stendencyisto

A

movebackintotheblood.

208
Q

UnliketheCHP,theBCOPremains

A

constantacrossthecapillarybedat25mmHg.Why?Becausetheconcentrationofnonpenetratingsolutesdoesnotchangefromoneendofthecapillarybedtotheother.

209
Q

Filtrationoccursonlyatthe

A

arterioleendofthecapillarybed.

210
Q

Thisprocessoffilteringthebloodplasmaistheonlywaythebodyhasto

A

createinterstitialfluid.

211
Q

Theinterstitialfluidisthendrainedintothe

A

lymphaticsystemtobecomelymph

212
Q

Reabsorptionofwateroccursonlyatthe

A

venuleend.

213
Q

somewaterisalwaysreabsorbedatthevenuleendofthecapillarybecauseof

A

osmosis.

214
Q

Thecapillaryhydrostaticpressure(CHP)isthe

A

bloodpressureinsidethecapillary.

215
Q

Venousreturnrefersto

A

thevolumeofbloodreturningtotheheartthroughtheveins.

216
Q

Veinsareundermuchlowerpressurethanarteries,whichmakesitdifficulttoreturnvenousbloodtotheheart. TRUE OR FALSE

A

TRUE

217
Q

Veinscontain________atregularintervals,whichallowforbloodflowinonedirectionandpreventbackflow.

A

semilunarvalves

218
Q

Venousreturniseasierwhenapersonislyingdownbecause

A

theforceofgravityisnotafactor.Butwhensomeoneisstandingup,considerhowlongajourneyitisforthevenousbloodinyourfoottoreturntotheheartwhilemovingagainstgravity.

219
Q

Althoughtheheart’snormalpumpingactionhelpsmovethevenousbloodbacktotheheart,thebodyhastwoothermechanisms

A

(1)skeletalmuscle“pump,”and(2)respiratory“pump.”

220
Q

Whenyouarewalking,thenormalmusclecontractionsinyourlegsgreatlyaid

A

invenousreturn.Theyactuallysqueezebloodupthroughtheperipheralveinstowardtheheartinanactioncalled“milking.”

221
Q

milking

A

Hereishowitworks:Theillustrationshowsashortsegmentofaveinwithtwosemilunarvalves.Theproximalvalveisnearertheheart,andthedistalvalveisfartherfromtheheart.Astheskeletalmusclearoundthisveincontracts,thevesselissqueezed,therebyincreasingthepressureinsidethevein.Thisincreasedpressureforcestheproximalvalvetoopen,butthedistalvalveremainsclosedbecauseofbackpressure.Theendresultofthisactionisthatsomevenousbloodismovedupintothenextsectionofthevein.Byrepeatingthispattern,venousbloodisgivenanextrapushonitsjourneybacktotheheart.

222
Q

Ifyouhavetostandforalongtime,itisgoodtoflexyourgastrocnemiusmuscles(calfmuscles)toprevent

A

fainting.

223
Q

Faintingiscausedbya

A

decreaseinvenousreturn,whichleadstodecreasedcardiacoutput,whichcausesadecreaseinthebloodsupplytothebrain.Thismeansthatlessoxygenandglucosearebeingdeliveredtoneuronsinthebrain,whichcausesfainting.

224
Q

Byflexingyourgastrocnemiusmusclesafterstandingstillforalongtime,youwillputyour__________toworkforyou.

A

skeletalmuscle“pump”

225
Q

Normalbreathingfacilitates

A

venousreturn.Thedeeperthebreathing,thegreateristheassistanceinthisregard.

226
Q

Normalbreathinginvolvesarepeatingcycleof

A

contractionandrelaxationofthediaphragm.

227
Q

Whenthisdiaphragm contractsforanormalinspiration,itmovesdownwardand

A

compressesthecontentsoftheabdominalcavity,whichincreasestheabdominalpressure.Simultaneously,thevolumeinthethoraciccavityincreases,causingadecreaseinpressure.Thispressuregradientforcesbloodoutofthevariousveinsintheabdominalregionandintotheinferiorvenacava(IVC)toallowbloodtomovebackintotherightatriumoftheheart.

228
Q

Cardiac output (CO) is

A

the amount of blood pumped out of a ventricle in 1 minute and is expressed as milliliters of blood per minute. It is mathematically defined as the product of the stroke volume (SV) times the heart rate (HR)

229
Q

A normal stroke volume is the amount of

A

blood pumped out of each ventricle in one beat—about 70 mL for an adult heart.

230
Q

A healthy adult male has a resting heart rate of about

A

70 beats per minute

231
Q

In general, factors that effect SV also affect

A

HR. For example, during exercise, both SV and HR increase

232
Q

FactorsaffectingSV

A

preload, contractility; afterload

233
Q

Preload:

A

definedastheamountoftensionintheventricularcardiacmusclecellspriortocontracting.Theruleisthatthegreaterthetensiononthecells,themoreforcefullytheycontract.

234
Q

Frank-StarlingLaw.

A

ThisrelationshipisreferredtoastheForexample,duringexercise,morebloodisreturnedtotheheartthroughthevenousreturn.Asmorebloodenterstheheart,itstretchescardiacmusclescells,resultinginamoreforcefulejectionofblood.Forthisreason,exerciseincreasesSV.

235
Q

Contractility:definedas

A

thedegreetowhichcardiacmusclecellscanshortenwhenstimulatedbyaspecificchemicalsubstance.Forexample,calciumionshaveapositiveinfluenceoncardiacmusclecontraction.Abnormallylowlevelsofcalciumresultinanirregularheartbeat,decreasingtheSV.

236
Q

Afterload:definedas

A

theamountofforceneededfromventricularcardiacmusclecellstoejectbloodfromtheventriclesandpastthesemilunarvalves.Anythingthatimpedesbloodflowcanincreaseafterload.Forexample,anyblockageintheperipheralbloodvessels(suchasatherosclerosis)wouldrestrictbloodflowandincreasetheafterload.Hypertension(highbloodpressure)alsoincreasestheafterload.Astheafterloadincreases,theSVdecreases.

237
Q

FactorsaffectingHR

A

age, sex, state of activity, endurance training, stress, anxiety

238
Q

Age:

A

HRgraduallydecreasesfromchildhoodtoadulthood.AnewbornmayhaveanHRof120bpm,whereasanadultmalemayhave70bpm.Intheelderly,theHRincreasesagainrelativetothatofayoungadult.

239
Q

●Sex:

A

Onaverage,femaleshaveslightlyhigherrestingHRsthanmales.Thedifferenceisabout5bpm.

240
Q

●Stateofactivity:

A

Duringcertainphasesofthesleepcycle,theHRdecreases.ButduringexercisetheHRtemporarilyincreases.

241
Q

●Endurancetraining:

A

MarathonrunnersmayhavearestingHRof50bpm.ThistypeoftrainingincreasesheartsizeaswellasSV.ThisallowsforanormalCOwithalowerHR.

242
Q

●Stress,anxiety:

A

StressandanxietyincreaseHR.

243
Q

TheCOdoesnotremainconstant. True or False

A

Itregularlyrisesandfalls.

244
Q

MaintainingtheCOinanormalrangeisprimarilythejobofthe

A

cardiovascular(CV)centerinthemedullaoblongataofthebrain.

245
Q

Usingreflexpathwaysinthe

A

autonomicnervoussystem,theCVcenterregulatestherhythmandforceoftheheartrate.

246
Q

Hormonesalsohelptocontrol

A

cardiacactivity.

247
Q

Forexample,epinephrineandnorepinephrinearepowerful

A

cardiacstimulators.

248
Q

Inshort,thenervoussystemandhormonalregulatorsworktogethertoregulate

A

heartactivity,therebyindirectlyensuringthatanormalCOisachieved.

249
Q

Heartrate(HR)isthenumberof

A

heartbeatsperunittime,typicallyexpressedasbeatsperminute(bpm).Anormalaverageis 70bpm.

250
Q

Strokevolume(SV)istheamountof

A

bloodpumpedoutofeachventricleinonebeat(BPM),expressedinmilliliters(mL)ofblood.Anormalvalueis70mL.

251
Q

Cardiacoutput(CO)istheamountof

A

bloodpumpedoutoftheleftventricleinoneminute,expressedinmilliliters(mL)ofbloodperminute.Anormalvalueis4,900mL/min.

252
Q

Thefollowingfourregulatorymechanismsareusedtocontrolbloodpressure(BP):

A

cardiovascularcenter,neuralregulation,hormonalregulation,andautoregulation.

253
Q

1Neuralregulationthroughthecardiovascularcenter

A

Neuralregulationusesreflexpathwaystoregulatenormalbloodpressure.Asitsnameimplies,thecardiovascularcenter(CV),inthemedullaoblongata,isthenervoussystem’scommand-and-controlcenterforregulatingtheheartrateandvasoconstriction.

254
Q

thecardiovascularcenter(CV),inthemedullaoblongatareceivesperipheralsensoryinputfromthreemajorsources:

A

proprioceptors,chemoreceptors,andbaroreceptors.TheCVrespondsbysendingtheappropriatemotoroutputtotheheartandbloodvessels.Dependingonthestimulus,theheartrate(HR)eitherincreasesordecreases,andbloodvesselsarestimulatedtoconstrict.TheendresultisthattheBPeitherincreasesordecreasesbacktonormallevels.Fordetailsofthesereflexpathways

255
Q

proprioceptors

A

(detectchangesinmuscletension),

256
Q

chemoreceptors

A

(detectchangesinbloodacidity),

257
Q

andbaroreceptors

A

(detectchangesinbloodpressure)

258
Q

Hormonalregulationinvolvestheuseof

A

chemicalmessengerscalledhormonesthatbindtoreceptorsatatargettissueinordertoinducearesponse.

259
Q

●Renin-angiotensin-aldosterone(RAA)system

A

Whenbloodpressuredecreases,itstimulatesthekidneytoreleasetheenzymereninintotheblood.ThisleadstotheproductionofapowerfulvasoconstrictorcalledangiotensinII.This,inturn,stimulatestheadrenalcortextoproducethehormonealdosterone.Thenetresultisanincreaseinbloodpressure.

260
Q

renin

A

??

261
Q

angiotensinII

A

vasoconstrictor

262
Q

●Epinephrine(EPI)/norepinephrine(NE)EPIandNEareproducedby

A

cellsintheadrenalmedullainresponsetoemergencyorstressfulsituations.Twooftheorganstheytargetaretheheartandbloodvessels.Theresultisthatheartrateincreasesandbloodvesselsconstrict,respectively.Together,thesetworesponsesleadtoanincreaseinbloodpressure.

263
Q

Waterlossfromtheblood,likewhatoccursduringexcessivesweating,stimulatesthe

A

posteriorlobeofthepituitaryglandtoproduceADH.Thishormonetargetsthenephronsinthekidneysandcausesmorewatertobereabsorbedintotheblood,thusrestoringnormalbloodpressure.

264
Q

Asbloodvolumeincreases,thisstretchestheatriaintheheart,whichstimulatescellsintheatriatoproduce

A

●Atrialnatriureticpeptide(ANP); ANP.Byincreasingvasodilation,sodiumionexcretion,andurineproductionandblockingthereleaseofhormoneslikeADHandaldosterone,ANPdecreasesBP.

265
Q

3Autoregulation—

A

theautomaticcontrolofbloodflowtoatissue;

266
Q

Thesemechanismsarenormallynotassignificantastheneuralandhormonalmechanisms

A

physical changes; chemical changes

267
Q

●Physicalchanges

A

ChangesinbodytemperatureaffectBP.Forexample,coldcausessuperficialbloodvesselstoconstrict,whichincreasesBP.Incontrast,heatcausesbloodvesselstodilate,leadingtoadecreaseinbloodpressure.

268
Q

●Chemicalchanges

A

Differenttypesofbodycells,suchassmoothmusclescells,endothelialcells,andmacrophages,producevariouschemicalsthatsignalbloodvesselstoeitherdilateorconstrict.Forexample,smoothcellsproducelacticacid,whichcausesbloodvesselstodilate.Othervasodilatingchemicalsincludenitricoxide(NO),H,andK.

269
Q

Whatisthehepaticportalsystem?

A

Thetermhepaticreferstotheliverandthetermportalreferstoaportalvesselwhichisdefinedasabloodvesselthatcarriesbloodfromonecapillarynetworktoanother.Allthebloodvesselsassociatedwiththisnetworkconstituteasystem.

270
Q

Thefirstcapillarynetworkisfoundin

A

allthedigestiveorgans

271
Q

Secondcapillarynetworkislocatedin

A

theliver(thecapillariesherearecalledsinusoids).Thevesselthatlinksthemtogetheristhehepaticportalvein.Thiswidevesselislabeledas#1intheillustrationonthefacingpage.Placeyourfingeronitandnoticethat

272
Q

sinusoids

A

capillaries found in the liver

273
Q

hepaticportalvein

A

??

274
Q

??

A

therearemanyvesselsdrainingdeoxygenatedbloodfromthedigestiveorgansandcarryingitthroughthehepaticportalveinandintotheliver. Thebloodvesselsinthissystemcarrynutrient-richbloodtotheliversothenutrientscanbeprocessedinlivercellsbeforeenteringthegeneralcirculation.Thedeoxygenatedvenousbloodinthissystemisdifferentfromnormalvenousbloodinthatthelevelofnutrientssuchasglucoseandaminoacidsismuchhigher.Forexample,afterameal,bloodglucoselevelsriseandexcessglucoseneedstobedeliveredtolivercellswhereitisstoredasglycogen.Afterallthesenutrientshavebeenprocessedinlivercells,thenthedeoxygenatedbloodisdrainedbythehepticveins(#2intheillustration)whichcarrybloodtotheinferiorvenacava(labeledintheillustration)whereitentersthegeneralcirculation.

275
Q

Therearethreemajorveinsthatdrainthebloodintothehepaticportalvein:●

A

Superiormesentericvein(#10); ●Inferiormesentericvein(#9); ●Splenicvein(#8)

276
Q

Superiormesentericvein(#10)

A

bloodvesselstotheleftthataredrainingbloodfrompartofthelargeintestine.Alsonoticethebloodvesselsdrainingbloodfromthepancreasandthebottomofthestomach.Doyouseethewordsduodenumandileumintheillustration?Thesearetwoofthethreepartsofthesmallintestineandbloodisbeingdrainedfrombothofthem.Thethirdpart,thejejunum,isnotshownintheillustration.Evenso,youcanseebloodvesselsbranchingofftherightsideofthesuperiormesentericveinthathavebeencut.Thesearedrainingtherestofthesmallintestinethatisnotshown.

277
Q

●Inferiormesentericvein(#9)

A

Noticethatitdrainsbloodfromtherectumandthedistalportionofthelargeintestine.Asyoufollowitupwards,noticethatitmergeswiththesplenicvein(#

278
Q

●Splenicvein(#8)

A

Thenamesplenicobviouslyinformsusthatitdrainsbloodfromthespleen,butifyoulooknearitsterminus,youwillseethatitalsodrainsbloodfrompartofthestomach.Lastly,ifyoulookatthepancreas,youcanseethatitalsodrainsbloodfromthepancreasviathepancreaticveins(#7).

279
Q

TheFetalcirculationisdifferentfrom

A

adultbloodcirculation.Thisistobeexpectedifyougiveitsomethought.Althoughthefetalheartisfunctioningandpumpingthefetalblood,thefetallungsarecollapsedandfilledwithfluid,sotheyarenotfunctioningforgasexchange.Thekidneysarealsonotfunctioningtoremovefetalwasteproductsfromtheblood.Noneofthedigestiveorgansarefunctioningbecausenofoodisbeingingested,sonutrientscannotbeobtained.Whatreplacesthesenonfunctionalorgansinthefetus?Theplacenta,theorganinthemother’suterus,isthesiteforexchangingbloodgases(O2andCO2),removingwasteproducts,andobtainingnutrients.Thisiswhyitissoimportantforapregnantwomantomaintainahealthydiet.Thefetus’slifelineistheumbilicalcord,abendable,cable-likestructurethatconnectsthefetustotheplacenta.

280
Q

pathwaythatbloodflowsinfetalcirculation.

A

pairofumbilicalarteriesthatbranchofftheinternaliliacarteriesandcarrythefetalbloodtotheplacentatobecomeoxygenated.Thenewlyoxygenatedbloodfromtheplacentaflowsthroughthesingleumbilicalveintothenonfunctionalliverwhereitconnectstotheductusvenosusthatdrainsintotheinferiorvenacava.Thedeoxygenatedbloodfromtheinferiorvenamixeswiththeoxygenatedbloodfromtheductusvenosustobecomemixedbloodenteringtheheart.Bloodthendrainsfromboththesuperiorvenacavaandtheinferiorvenacavaintotherightatrium(RA).BloodintheRAfollowstwodifferentpaths.SomeofthebloodintheRAgoesthroughanopeningwithaflapcalledtheforamenovaleandenterstheleftatrium(LA).Theremainingbloodenterstherightventricle,andthenflowsintothepulmonarytrunk.Interestinglyenough,bothpathwaysendupbypassingthenonfunctionallungs.Bloodintheleftatriumispumpedintotheleftventricle,flowsthroughtheaorticarch,andmovesintothesystemiccircuit.Whileasmallamountofbloodinthepulmonarytrunkgoestothelungs,almostallofitispumpedthroughtheductusarteriosus—ashortfetalbloodvesselthatconnectsthepulmonarytrunktotheaortaanddivertsthebloodintothesystemiccircuit.Asthemixedbloodmovesthroughthecommoniliacarteryandintotheinternaliliacartery,itenterstheumbilicalarteriesonceagaintorepeatthecycle.

281
Q

Afterbirth,theumbilicalcordistiedoffandblooddoesn’tflowthroughitanymore.Thefollowingkeychangesoccur:

A

●Umbilicalarteriescloseandbecomefibrouscordsattheirdistalends.

282
Q

●Foramenovaleclosesandsealsofftobecomea

A

shallowdepressionintheinteratrialseptumcalledthefossaovalis.

283
Q

●Ductusarteriosus—closestobecomethe

A

fibrousligamentumarteriosum.

284
Q

Theumbilicalveinclosestobecomethe

A

fibrousligamentumteres(roundligament).●

285
Q

Ductusvenosusclosestobecomethe

A

fibrousligamentumvenosum.

286
Q

Thearterialsystemintheheadandneckfeedsoxygenatedbloodtothe

A

brain,face,eyes,neck,larynx,pharynx,esophagus,andotherimportantstructures.

287
Q

Thearteriesbranchingofftheabdominalaortafeedoxygenatedbloodto

A

thedigestiveorgans,kidneys,spleen,gonads,urinarybladder,andotherimportantstructuresintheabdominopelviccavityandthelowerlimbs.

288
Q

Thearterialsystemintheupperlimbsfeedsoxygenatedbloodto

A

allthetissuesinthearms.

289
Q

Thearterialsysteminthelowerlimbsfeedsoxygenatedbloodto

A

allthetissuesinthelegs.

290
Q

Thevenoussystemintheheadandneckdrainsdeoxygenatedbloodfrom

A

thebrain,face,eyes,neck,larynx,pharynx,esophagus,andotherimportantstructures.

291
Q

Thevenoussystemintheabdominopelviccavitydrainsdeoxygenatedbloodintothe

A

inferiorvenacava,whichemptiesintotherightatriumoftheheart.

292
Q

Thevenoussystemintheupperlimbsdrainsdeoxygenatedbloodfrom

A

allthetissuesinthearms.

293
Q

Thevenoussysteminthelowerlimbsdrainsdeoxygenatedbloodfrom

A

allthetissuesinthelegs.

BIO 202 (14 decks)

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