NBME 23 Heart rate (NBME Answers)

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NBME 23 Answers ↦

nbme23/Block 1/Question#49 (64.6 difficulty score)
Electrical stimulation of the stellate ...
Heart rate🔍,📺
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+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. +8

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(1583),

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o,S 1T65T/-/2 ear eht hcesiapmtty eellv ofr the tehar. hTe tltesael onainglg rea lraccive teamticpysh ogalnng.i Tshi itonequs msees meor rtccinore (or a geuh p)ela ot em. utB ,eyh I nwok ppoeel lilw isdeeagr.

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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hTe way I eeculxdd atndosiiaolv swa :isth hte ecyipmsttah ecpreotr hatt lsitade si ,β2 wchih is otn adtsmitleu yb nnirreopp.ehine So to atmtesuil teh r,pcoeetr the lsalette inoaggnl udwlo avhe adh to irstf atslmueit het raadenl dmalule to slreaee nieriepepnh taltee(sl too hhgi ot eialmttsu hte m.ela)lud

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

+1
submitted by realmedicmd(2),

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I eroiryntlcc ecsho aoontildavsi. dFoun otu htat ist’ alyltauc rtsnicisctoonova lasdtio(aoniv is cyehai)rtmta:paps

ucmAonoit vreen iberfs are slao rillccauy nedvliov in teh utnrieagol fo urasaclv fscefet in het .isnk tyimSetpcah erevn sbiefr esereal rpeeiionhnrenp andr/o PNY to tinerneav alsrret,oie stnarreueovio m,soaotssean adn usnveo sisodnisu hhwic stulser ni anoroiivtosnc,tsc ershaew taipcaeshtpmyar evsnre eetmida taanoiotlsaidv hhguort oitavcnait fo nousev sieisdnuso by het sleerea fo ACh and itdPpI/peeV ideniihts htimnone.ie

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+0
submitted by consistentwrongdoer3(19),

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I huhgtot atth the imrarpy tsiycmpateh oaintvrnien ot teh earth wsa grhhtuo T-.1T4 hWy doulw taosnltmiiu of stih nnaoiglg otn fceaft iksn vselses in the ppuer ml?bi

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. +35

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(14),

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het teeslatl galgnnoi is rtpa fo eth epmahctiyst esunvro sytsme igfthl ro hgi.tf caersenI etarh tera si teh otms ibvu.oso