NBME 23 Heart rate (NBME Answers)

NBME 23 Answers ↦

nbme23/Block 1/Question#49 (61.2 difficulty score)
Electrical stimulation of the stellate ...
Heart rate🔍
tags:

+7
submitted by kentuckyfan(43),

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drzed Vasodilation of the skin is under sympathetic control as well -- beta-2 receptors when stimulated cause vasodilation (via increase of cAMP in vascular smooth muscle). The key is recognizing that stimulation of a GANGLION of the pns will lead to release of NOREPINEPHRINE, which preferentially stimulates alpha-1 receptors. Those receptors will cause vasoconstriction. If the question asked what happens when you stimulate the adrenal medulla, the answer would be (potentially) vasodilation. This is because the adrenal medulla releases EPINEPHRINE which preferentially stimulates beta-1/2 receptors. +6

jesusisking @drzed Awesome explanation except I think sympathetic response induces vasoconstriction in the skin though vasodilation in the muscles! +1

usmile1 @jesusisking yes you are correct! α1: vasoconstriction in skin and intestine ; β2: vasodilation in skeletal muscle (transmitter: only epinephrine!) +

Stellate ganglion is the result of fusion of inf cervical symp ganglion and T1 symp ganglion heart is supplied by T1-T4 so it will lead to increase HR

+3/- mhmdreyad(3),

+7
submitted by seagull(1443),

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,oS /TT1/-562 era the itepcmystah eevll rfo hte .thrae eTh steltlae oglnigan rea leacrciv shmcatpeiyt onigln.ag Tish usneqoti smsee ermo corcitern (or a heug lp)ae to me. But y,he I kwon lepepo iwll igr.eeasd

dentist you're right! heart rate is the only option under sympathetic control. +

drzed The cervical ganglion is a fusion of the last few cervical levels and the first thoracic level, so it is plausible. +

+2
submitted by real_rawgary(2),

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The way I udcedlex antoodviaisl asw tsih: teh spiehcttyma rpectero hatt asedilt si β,2 whcih si ont tsieldmtua yb rpehno.piernnie So to ieltsmaut teh etcrp,oer teh sltetela ilnoaggn doulw hvae adh to risft ailtuemts eth lndaaer elmldau to aeelesr pihpnreneei tt(aelsle oot high ot atiultems het ue.dlml)a

krewfoo99 But isint beta 1 (heart rate) also stimulated by Epinephrine? +

+1
submitted by realmedicmd(2),

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I cltirrnyeco shoce ndtvoailaios. undoF out ttah s’ti yluacatl tirnncicssoaoovt oi(stlaaoivnd is h)pcsiattmpaye:ra

iuAmnooct evrne iresfb ear saol crulcylia onvveidl in the reultgaion of lasrvuca tfeecfs ni eht kins. Stahyitepcm vnere seribf eesaelr prenneihiorepn d/naro YPN ot nteeiranv ierroes,tla uoeerrvastoni oa,tsosesmna nda neousv ussosnidi icwhh susertl ni istvooasi,nrcntoc ehawesr pmtepcatariyahs neresv imtdeea tsoinaidloatav ughroth taaivotnci fo nevuos dosnsuesii by the aeresle fo hCA dna iVdIepe/Ppt iiistednh enethminoi.

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+0
submitted by consistentwrongdoer3(17),

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I ghhutot that teh rraipym cyshitpaemt aviitnrnnoe ot eth thrae was ohtuhgr T-T14. yWh uwlod lnosmattiiu of hist goiangnl nto tefafc knsi ssselev ni eht prpue l?bim

methylased Stellate ganglion --> sympathetics for sweat to skin in UE + head. Apparently also to increase HR (some cardiologists ablate stellate ganglion for tachy that cant be controlled by beta blockers). +

tea-cats-biscuits The stellate ganglion is a sympathetic ganglion, so it wouldn’t increase vasodilation in the skin of the upper extremity. Also in most people, the inferior cervical ganglion is fused with the first thoracic ganglion (T1), forming the stellate ganglion. +30

sympathetikey Got this wrong too. I think upper extremity skin vasodilation (which I picked) is probably more due to local metabolites. +

+0
submitted by criovoly(13),

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the teslalte inoaggnl is rtap fo hte atpectyhmsi nsveoru esystm fihlgt ro tgfih. srcIneea terah raet si hte omts ou.voibs