EXAM 1 NUR 232 FUNCTION OF THE
HEART EXAM QUESTIONS AND
ANSWERS
-5nANSWERS--
The5ncardiac5nconduction5nsystem5ngenerates5nand5ntransmits5nelectrical5nimpulses5
nthat5nstimulate5ncontraction5nof5nthe5nmyo-
5ncardium.5nUnder5nnormal5ncircumstances,5nthe5nconduction5nsys-
5ntem5nfirst5nstimulates5ncontraction5nof5nthe5natria5nand5nthen5nthe5nventricles.5nThe5
nsynchronization5nof5nthe5natrial5nand5nventricular5nevents5nallows5nthe5nventricles5nto
5nfill5ncompletely5nbefore5nven-
5ntricular5nejection,5nthereby5nmaximizing5ncardiac5noutput.5nThree5nphysiologic5nchar
acteristics5nof5ntwo5ntypes5nof5nspecialized5nelec-
5ntrical5ncells,5nthe5nnodal5ncells5nand5nthe5nPurkinje5ncells,5nprovide5nthis5nsynchroni
zation:
•5nAutomaticity:5nability5nto5ninitiate5nan5nelectrical5nimpulse5n•5nExcitability:5nability5nt
o5nrespond5nto5nan5nelectrical5nimpulse5n•5nConductivity:5nability5nto5ntransmit5nan5nel
ectrical5nimpulse
from5none5ncell5nto5nanother5nBoth5nthe5nsinoatrial5n(SA)5nnode5n(the5nprimary5npace
maker
of5nthe5nheart)5nand5nthe5natrioventricular5n(AV)5nnode5n(the5nsec-
5nondary5npacemaker5nof5nthe5nheart)5nare5ncomposed5nof5nnodal5ncells.5nThe5nSA5n
node5nis5nlocated5nat5nthe5njunction5nof5nthe5nsuperior5nvena5ncava5nand5nthe5nright5n
atrium5n(Fig.5n25-
3).5nThe5nSA5nnode5nin5na5nnormal5nresting5nadult5nheart5nhas5nan5ninherent5nfiring5nr
ate5nof5n605nto5n1005nimpulses5nper5nminute;5nhowever,5nthe5nrate5nchanges5nin5nres
ponse5nto5nthe5nmetabolic5ndemands5nof5nthe5nbody5n(Weber5n&5nKelley,5n2010).
The5nelectrical5nimpulses5ninitiated5nby5nthe5nSA5nnode5nare5ncon-
5nducted5nalong5nthe5nmyocardial5ncells5nof5nthe5natria5nvia5nspecial-
5nized5ntracts5ncalled5ninternodal5npathways.5nThe5nimpulses5ncause
5n(L.5n657)
L.,5nHinkle,5nJ.,5nCheever,5nH..5nBrunner5n&5nSuddarth's5nTextbook5nof5nMedical-
Surgical5nNursing,5n13th5nEdition.5nLippincott5nWilliams5n&5nWilkins,5n12/2013.5nVital
Book5nfile.
What's5nthe5nfunction5nof5ncardiac5nconduction5nsystem?5n-5nANSWERS--
generates5nand5ntransmits5nelectrical5nimpulses5nthat5nstimulate5ncontraction5nof5nthe
5nmyo-5ncardium.
Conduction5nsystem5nkeeps5nthings5nin5norder.5n
Under5nnormal5ncircumstances,5nthe5nconduction5nsys-
5ntem5nfirst5nstimulates5ncontraction5nof5nthe5natria5nand5nthen5nthe5nventricles.
HEART EXAM QUESTIONS AND
ANSWERS
-5nANSWERS--
The5ncardiac5nconduction5nsystem5ngenerates5nand5ntransmits5nelectrical5nimpulses5
nthat5nstimulate5ncontraction5nof5nthe5nmyo-
5ncardium.5nUnder5nnormal5ncircumstances,5nthe5nconduction5nsys-
5ntem5nfirst5nstimulates5ncontraction5nof5nthe5natria5nand5nthen5nthe5nventricles.5nThe5
nsynchronization5nof5nthe5natrial5nand5nventricular5nevents5nallows5nthe5nventricles5nto
5nfill5ncompletely5nbefore5nven-
5ntricular5nejection,5nthereby5nmaximizing5ncardiac5noutput.5nThree5nphysiologic5nchar
acteristics5nof5ntwo5ntypes5nof5nspecialized5nelec-
5ntrical5ncells,5nthe5nnodal5ncells5nand5nthe5nPurkinje5ncells,5nprovide5nthis5nsynchroni
zation:
•5nAutomaticity:5nability5nto5ninitiate5nan5nelectrical5nimpulse5n•5nExcitability:5nability5nt
o5nrespond5nto5nan5nelectrical5nimpulse5n•5nConductivity:5nability5nto5ntransmit5nan5nel
ectrical5nimpulse
from5none5ncell5nto5nanother5nBoth5nthe5nsinoatrial5n(SA)5nnode5n(the5nprimary5npace
maker
of5nthe5nheart)5nand5nthe5natrioventricular5n(AV)5nnode5n(the5nsec-
5nondary5npacemaker5nof5nthe5nheart)5nare5ncomposed5nof5nnodal5ncells.5nThe5nSA5n
node5nis5nlocated5nat5nthe5njunction5nof5nthe5nsuperior5nvena5ncava5nand5nthe5nright5n
atrium5n(Fig.5n25-
3).5nThe5nSA5nnode5nin5na5nnormal5nresting5nadult5nheart5nhas5nan5ninherent5nfiring5nr
ate5nof5n605nto5n1005nimpulses5nper5nminute;5nhowever,5nthe5nrate5nchanges5nin5nres
ponse5nto5nthe5nmetabolic5ndemands5nof5nthe5nbody5n(Weber5n&5nKelley,5n2010).
The5nelectrical5nimpulses5ninitiated5nby5nthe5nSA5nnode5nare5ncon-
5nducted5nalong5nthe5nmyocardial5ncells5nof5nthe5natria5nvia5nspecial-
5nized5ntracts5ncalled5ninternodal5npathways.5nThe5nimpulses5ncause
5n(L.5n657)
L.,5nHinkle,5nJ.,5nCheever,5nH..5nBrunner5n&5nSuddarth's5nTextbook5nof5nMedical-
Surgical5nNursing,5n13th5nEdition.5nLippincott5nWilliams5n&5nWilkins,5n12/2013.5nVital
Book5nfile.
What's5nthe5nfunction5nof5ncardiac5nconduction5nsystem?5n-5nANSWERS--
generates5nand5ntransmits5nelectrical5nimpulses5nthat5nstimulate5ncontraction5nof5nthe
5nmyo-5ncardium.
Conduction5nsystem5nkeeps5nthings5nin5norder.5n
Under5nnormal5ncircumstances,5nthe5nconduction5nsys-
5ntem5nfirst5nstimulates5ncontraction5nof5nthe5natria5nand5nthen5nthe5nventricles.
