share email twitter ⋅ join discord whatsapp(2ck)
free120  nbme24  nbme23  nbme22  nbme21  nbme20  nbme19  nbme18  nbme17  nbme16  nbme15  nbme13 

NBME 21 Answers

nbme21/Block 1/Question#34 (57.2 difficulty score)
A 30-year-old man develops urinary ...
Pelvic nervesπŸ”
tags:

Login to comment/vote.


 +9 
submitted by hungrybox(968),
unscramble the site ⋅ remove ads ⋅ become a member ($39/month)

yohnmecaiys dsoetp hsit garte pic lebwo

eacv  here is a video for ilustration https://www.youtube.com/watch?v=US0vNoxsW-k +2  

Based off this pic:

External urinary sphincter: inhibits (via pudendal nerve) Hypogastric nerve: Ξ±1 receptor β†’ contracts internal urethral sphincter β†’ inhibits Pelvic nerves Correct! M3 receptor β†’ contracts detrusor muscle Pudendal nerve: inhibits (Nictonic receptor) β†’ contracts external urethral sphincter β†’ inhibits

+1/- hungrybox(968),

External urinary sphincter inhibits (via pudendal nerve)

Hypogastric nerve Ξ±1 receptor β†’ contracts internal urethral sphincter β†’ inhibits

Pelvic nerves Correct! M3 receptor β†’ contracts detrusor muscle

Pudendal nerve: inhibits (Nictonic receptor β†’ contracts external urethral sphincter β†’ inhibits

+/- hungrybox(968),


 +5 
submitted by peridot(57),

Here is my summary of the picture/video that was posted:

There are 3 pathways involved in peeing:

  1. Pelvic n. (aka pelvic splanchnic n.) sends parasympathetic fibers to deltrusor to contract --> squeeze bladder and pee.

  2. Hypogastric n. sends sympathetic fibers to the deltrusor to relax, as well as the internal sphincter to contract --> hold back pee

  3. Pudendal n. sends somatic fibers (under conscious control) to the external sphincter to contract --> hold back pee

In this question, the patient's bladder is filling up so much that it's forced to overflow. That means there is a problem with scenario 1 - damage to pelvic n. so that he can't squeeze his bladder even when it's super full.

peridot  To clarify, this description is meant to go along with @hungrybox's pic link and @eacv's video link +4  
lovebug  thanks a lot! +  



 +3 
submitted by neonem(550),
unscramble the site ⋅ remove ads ⋅ become a member ($39/month)

heT aslarc imtuintoicr treenc is 1 fo 3 ptmensocno fo ioitumnritc xelfre (other 2 ear morf epiontn irclatuer otirnmafo dan ralrbeec x)ort.ce Sclraa mtci rtenec = 24S-S sanlip dcro lvlee gitlnvare mfor anrtelv tihew meratt ni hte Piclev eevsnr, eneosrsibpl rfo ardlbde oonitctrcan iav hte gliconcierh senevr (hntki ti atsc no the 3M peceotrr ni eth leddbar or?td.u)rse fI uyo elos eeths sreevn e(..i in civple cetu)r,rfa wlil slretu ni rolfwove nnoinnitceec.




 +2 
submitted by meryen13(13),

pelvic nerve--> increases voiding urine, m3 receptor, parasympathetic hypogastric nerve--> increases urinary retention, sympathetic, beta 3 and alpha1 receptors. pudendal nerve--> not part of micturition, its a somatic component and has a nicotinic receptor.




 +1 
submitted by yo(78),
unscramble the site ⋅ remove ads ⋅ become a member ($39/month)

iisrlygnrspu doog oianneplaxt nda cpreitu oundf on tsih sie.t nhsigotme aognl eht nelsi fo uinaoirittmnc xeerfl (aak labdred is lulf and ouy piss )xefelr is gone so teh effetanr iesbrf gcirrnya eth lnaigs atht the ebladdr is lulf traen' g.nwrkio toehs esfibr rae crraied in hte peiclv nevres

t/ts/:peoi/dirssmwrtw/roopuopo.oyictxgn/.eiirterldmpgcwuyt/t-coc/bu

yo  if still confused, a better explanation can be found here https://courses.washington.edu/conj/bess/urination/urination.html +18  
hyoscyamine  i found this image to be helpful in remembering which nerves do what on which receptor. https://i.ytimg.com/vi/JwaeWXhklio/maxresdefault.jpg +7  
drdoom  ^ linkify hyoscyamine https://i.ytimg.com/vi/JwaeWXhklio/maxresdefault.jpg +  



 +0 
submitted by bbr(22),

I'm still confused, where is this guys problem occuring? Is that he is unable to urinate, or that he has overflow incontinence? Getting lost in these nerves.