EVOLVE: CHAPTER 31 EXAM 4 QUESTIONS AND CORRECT ANSWERS

EVOLVE: CHAPTER 31 EXAM 4
QUESTIONS AND CORRECT ANSWERS

WhichA2waveformA2onA2theA2ECGA2indicatesA2properA2functionA2ofA2theA2sinoatrialA2(SA)A2
node?A2(31)

TheA2STA2segmentA2isA2elevated.

TheA2QRSA2complexA2isA2present.

TheA2PRA2intervalA2isA20.24A2seconds.

AA2PA2waveA2precedesA2everyA2QRSA2complex.A2-A2Ans--
AA2PA2waveA2precedesA2everyA2QRSA2complex.


AA2PA2waveA2isA2generatedA2byA2theA2SAA2nodeA2andA2representsA2atrialA2depolarization.A
2WhenA2theA2electricalA2impulseA2isA2consistentlyA2generatedA2fromA2theA2SAA2node,A2the
A2PA2wavesA2haveA2aA2consistentA2shapeA2inA2aA2givenA2lead.A2ElevationA2ofA2theA2STA2se
gmentA2indicatesA2myocardialA2injury.A2TheA2QRSA2complexA2representsA2ventricularA2de
polarization.A2TheA2PRA2intervalA2representsA2timeA2requiredA2forA2atrialA2depolarizationA2
andA2forA2theA2impulseA2delayA2inA2theA2atrioventricularA2nodeA2andA2travelA2timeA2toA2theA
2PurkinjeA2fibers.


WhichA2componentA2ofA2aA2patient'sA2conductionA2systemA2isA2identifiedA2byA2theA2circled
A2partA2ofA2theA2ECGA2waveform?A2(31)


AtrialA2kick

AtrialA2depolarization

VentricularA2contraction

T-cellA2(transitionalA2cell)A2impulseA2slowingA2-A2Ans--AtrialA2depolarization


AtrialA2depolarizationA2isA2representedA2byA2theA2PA2waveA2onA2theA2ECG.A2TheA2"atrialA2k
ick"A2isA2whenA2theA2atriaA2contractsA2andA2theA2ventriclesA2fill;A2thisA2eventA2occursA2after
A2theA2PRA2interval.A2VentricularA2contractionA2occursA2afterA2ventricularA2depolarizationA2
(QRSA2complex).A2TA2cellsA2slowA2theA2impulseA2duringA2theA2PRA2interval.

WhichA2classA2ofA2antidysrhythmicA2drugsA2doesA2theA2nurseA2anticipateA2beingA2prescrib
edA2forA2theA2patientA2diagnosedA2withA2supraventricularA2tachycardiaA2associatedA2withA2
excessiveA2beta-adrenergicA2stimulation?A2(31)

,I

II

III

IVA2-A2Ans--II


ClassA2IIA2antidysrhythmicsA2controlA2dysrhythmiasA2associatedA2withA2excessiveA2beta-
adrenergicA2stimulation.A2ClassA2IA2drugsA2areA2membraneA2stabilizingA2agents.A2ClassA2I
IIA2drugsA2lengthenA2theA2absoluteA2refractoryA2andA2prolongA2repolarization.A2ClassA2IVA2
drugsA2slowA2theA2flowA2ofA2calciumA2intoA2theA2cellA2duringA2depolarization.

WhichA2isA2aA2functionA2ofA2TA2cellsA2inA2theA2atrioventricularA2(AV)A2junctionA2area?A2(31)

CausesA2theA2ventriclesA2toA2contract

HelpsA2toA2speedA2upA2impulsesA2toA2theA2ventricles

GeneratesA2impulsesA2spontaneouslyA2andA2rhythmically

CausesA2aA2delayA2inA2theA2conductionA2ofA2impulsesA2toA2theA2AVA2nodeA2-A2Ans--
CausesA2aA2delayA2inA2theA2conductionA2ofA2impulsesA2toA2theA2AVA2node


TheA2TA2cellsA2(transitionalA2zoneA2cells)A2causeA2aA2delayA2inA2theA2conductionA2ofA2impu
lsesA2toA2theA2AVA2node.A2ThisA2delayA2facilitatesA2adequateA2timeA2forA2atrialA2filling.A2Th
eA2conductionA2throughA2PurkinjeA2fibersA2causesA2theA2ventriclesA2toA2contract.A2TheA2S
AA2nodeA2generatesA2impulsesA2spontaneouslyA2andA2rhythmicallyA2inA2aA2normallyA2func
tioningA2cardiacA2electricalA2conductionA2system.A2TheA2AVA2nodeA2doesA2notA2speedA2up
A2impulsesA2toA2theA2ventriclesA2butA2ratherA2actsA2asA2aA2relayA2stationA2forA2electricalA2c
onductionA2andA2electricallyA2connectsA2atrialA2andA2ventricularA2chambers.

WhichA2specializedA2functionA2ofA2myocardialA2cellsA2givesA2themA2aA2pacingA2function?
A2(31)


Excitability

Contractility

Conductivity

AutomaticityA2-A2Ans--Automaticity

,Automaticity,A2alsoA2knownA2asA2pacingA2function,A2isA2theA2abilityA2ofA2theA2myocardialA2
cellsA2toA2generateA2anA2impulse.A2TheA2cellsA2thatA2generateA2theA2impulsesA2areA2called
A2primaryA2pacemakerA2cells;A2theyA2areA2mainlyA2locatedA2inA2theA2sinoatrialA2node.A2Exc
itabilityA2isA2theA2abilityA2ofA2nonpacemakerA2heartA2cellsA2toA2respondA2toA2anA2electricalA
2impulse,A2whichA2beginsA2inA2pacemakerA2cells.A2ContractilityA2isA2theA2mechanicalA2acti
vityA2ofA2theA2heart.A2ConductivityA2isA2theA2abilityA2toA2endA2impulsesA2fromA2cellA2membr
aneA2toA2cellA2membrane.

WhichA2willA2theA2nurseA2noteA2inA2theA2patientA2ifA2theA2sinoatrialA2(SA)A2nodeA2generate
sA2electricalA2impulsesA2atA2aA2higherA2rate?A2(31)

IncreasedA2heartA2rate

DecreasedA2bloodA2pressure

DelayedA2atrialA2depolarization

HinderedA2ventricularA2depolarizationA2-A2Ans--IncreasedA2heartA2rate


TheA2SAA2nodeA2generatesA2impulsesA2thatA2areA2conductedA2throughA2theA2heart.A2ThisA
2generationA2ofA2impulsesA2happensA2atA2aA2specificA2rate,A2whichA2canA2beA2measuredA2
asA2theA2heartA2rate.A2IfA2theA2numberA2ofA2electricalA2impulsesA2increases,A2theA2heartA2r
ateA2willA2increase,A2andA2theA2bloodA2pressureA2willA2increase.A2IfA2theA2SAA2nodeA2gene
ratesA2electricalA2impulsesA2atA2aA2higherA2rate,A2atrialA2andA2ventricularA2depolarizationA2
willA2occurA2atA2aA2higherA2rate.

WhatA2isA2theA2primaryA2pacemakerA2ofA2theA2heart?A2(31)

BundleA2ofA2His

PurkinjeA2fibers

SinoatrialA2(SA)A2node

AtrioventricularA2(AV)A2nodeA2-A2Ans--SinoatrialA2(SA)A2node


TheA2SAA2nodeA2isA2theA2primaryA2pacemakerA2ofA2theA2heart;A2itA2generatesA2theA2heart'
sA2electricalA2impulses.A2TheA2bundleA2ofA2HisA2andA2PurkinjeA2fibersA2areA2responsibleA2f
orA2rapidA2conductionA2ofA2impulsesA2throughA2theA2ventricles;A2theyA2areA2notA2theA2prim
aryA2pacemakersA2ofA2theA2heart.A2TheA2AVA2nodeA2causesA2impulsesA2toA2slowA2downA2
orA2toA2beA2delayedA2beforeA2proceedingA2toA2theA2ventricles.

, WhichA2statementA2accuratelyA2describesA2theA2areaA2ofA2theA2heartA2thatA2initiatesA2theA2
cardiacA2cycle?A2(31)

TheA2ventricles'A2PurkinjeA2fibersA2areA2responsibleA2forA2theA2initialA2cardiacA2impulse.

TheA2bundleA2ofA2HisA2actsA2toA2initiateA2cardiacA2contractionA2inA2theA2atriaA2withA2aA2res
ultingA2QRSA2complex.

TheA2atrioventricularA2areaA2actsA2asA2theA2primaryA2pacemakerA2andA2producesA2theA2PA
2waveA2onA2theA2ECG.


TheA2sinoatrialA2(SA)A2nodeA2isA2theA2primaryA2pacemakerA2ofA2theA2heartA2whoseA2activit
yA2isA2reflectedA2inA2theA2PA2waveA2onA2theA2ECG.A2-A2Ans--
TheA2sinoatrialA2(SA)A2nodeA2isA2theA2primaryA2pacemakerA2ofA2theA2heartA2whoseA2activit
yA2isA2reflectedA2inA2theA2PA2waveA2onA2theA2ECG.


TheA2SAA2nodeA2isA2theA2heart'sA2primaryA2pacemakerA2causingA2atrialA2depolarization,A2r
eflectedA2inA2theA2PA2waveA2onA2theA2ECG.A2TheA2PurkinjeA2fibersA2causeA2rapidA2conduc
tionA2ofA2impulsesA2throughoutA2theA2ventricles,A2causingA2ventricularA2depolarizationA2an
dA2contractionA2consistentA2withA2theA2QRSA2complex.A2TheA2bundleA2ofA2HisA2extendsA2d
ownA2theA2interventricularA2septumA2toA2bothA2ventricles.A2TheA2atrialA2junctionA2andA2atri
oventricularA2nodeA2receiveA2conductionA2fromA2theA2SAA2node,A2delayingA2conductionA2b
eforeA2sendingA2theA2impulseA2toA2theA2ventricles;A2thisA2isA2reflectedA2inA2theA2PRA2segm
ent.

WhichA2willA2theA2nurseA2documentA2asA2theA2heartA2rateA2ofA2aA2patientA2withA212A2QRSA
2complexesA2inA2theA26-secondA2strip?A2(31)


12A2beats/min

100A2beats/min

110A2beats/min

120A2beats/minA2-A2Ans--120A2beats/min


TheA2answerA2isA2determinedA2byA2multiplyingA212A2complexesA2byA210A2toA2reachA2theA2
heartA2rateA2perA260A2secondsA2(1A2minute):A2120A2beats/min.

WhichA2propertyA2ofA2theA2heartA2isA2relatedA2toA2mechanicalA2activity?A2(31)

Excitability

Conductivity