baroreceptor--
can any1 please explain me why this answer is wrong?
increased barorecptor afferent firing in the aortic arc leads to nicreased parasympathic effernt firing?
the question is:
what is the mechanism of the normal physiologic response to hypotension
a:decreased barorecptor aff firing in the aortic arc leads to increased symp eff firing--wrong
b:decreased barorecptor aff firing ni the carotid sinus leads to increased parasymp eff firing--wrong
c:decreased barorecptor aff firing in the carotid sinus leads to increased symp eff firing-true
d:increased barorecptor afferent firing in the aortic arc leads to increased parasympathic effernt firing--true??????
e:increased barorecptor aff firing in the carotid sinus leads to increased symp eff firing--wrong
go back to the Anatomy of Sympathetic and Parasympathetic.This is a physiology question with anatomy basics.As far as I remember the aortic arch or aortic sinus is supplied by vagus nerve which is predominantly parasympathetic.
devikabhatt wrote:
go back to the Anatomy of Sympathetic and Parasympathetic.This is a physiology question with anatomy basics.As far as I remember the aortic arch or aortic sinus is supplied by vagus nerve which is predominantly parasympathetic.
yes i know, so D should also be true-- but the correct answer is only C and not D
Oh ! yes there are some inhibitory parasympathetic neurons between this carotid body and those stellate or sympathetic ganglion.Dec Barorec afferent firing in carotid sinus leads to decreased parasymparthetic firing(the preganglionic ones) which leads to increased sympathetic (postganglionic ) firing.I have read this long time ago.So you better revise it from Anatomy and Pharmacology(ANS) of Kaplan notes/videos
reflex parasympathetic response develops to an increased baroreceptor firing (which occurs in hypertension). but in this case of hypotension there is reduced baroreceptor firing which triggers the sympathetic system to maintain the systemic pressure.
So the answer C is correct.
lET ME KNOW IF THE CONCEPT IS WRONG.
I agree with Kurma, The question is about HYPOTENSION n NOT HYPERTENSION. So Decreased Afferent leads to Increased
Sympathetic Firing is d only Best Answer I could find.
Corrct Me if Iam wrong...
DrRG2289 wrote:
I agree with Kurma, The question is about HYPOTENSION n NOT HYPERTENSION. So Decreased Afferent leads to Increased
Sympathetic Firing is d only Best Answer I could find.
Corrct Me if Iam wrong...
yes u r right.. i dont know why , but i thought all the time that the question is about HYPERtension not Hypotension--- thats what happen when u study 2 much
Thanks u all
The correct answer is C. Why? will leave the anatomy part for you to figure out!
Physiologically speaking,
During normal BP, the baroreceptors are firing> Medulla oblangata> + parasympathetic> balance the sympathetic(Prevent HT).
During hypotention: - Baroreflex> MO> + sympathetic in order to increase BP towards normal.
also during hypertension: + Baroreflex> + parasym> in order to lower BP towards normal.
edited by MeMe61363950 on 11/29/2012
edited by MeMe61363950 on 11/29/2012
oh no! I made the same mistake.The question says physiologic response to HYPOTENSION(what happens after hypotension),I thought its physiologic response underlying hypotension(what happens before hypotension).
The question is abt response to hypotension. The answer is C
Carotid sinus nerve respond to increase or decrease to BP. Aortic arch baroreceptors respond PRIMARILY to INCREASE in arterial pressure.
So in hypotension, Its the carotid. Hypotension will a decrese stretch on the baroreceptors and thus decreased firing rate of carotid sinus nerve -->medulla---->Decrease PNS to the heart thus increasing HR And Increase Sympathetic to the heart and blood vessels --->increase HR and CO and TPR--->increase BP
So-- in hypotension, there is decresed baroreceptor firing .
Yes.. You are Right !!
amircohen wrote:
DrRG2289 wrote:
I agree with Kurma, The question is about HYPOTENSION n NOT HYPERTENSION. So Decreased Afferent leads to Increased
Sympathetic Firing is d only Best Answer I could find.
Corrct Me if Iam wrong...
yes u r right.. i dont know why , but i thought all the time that the question is about HYPERtension not Hypotension--- thats what happen when u study 2 much
Thanks u all
devikabhatt wrote:
go back to the Anatomy of Sympathetic and Parasympathetic.This is a physiology question with anatomy basics.As far as I remember the aortic arch or aortic sinus is supplied by vagus nerve which is predominantly parasympathetic.
I think it's the carotid sinus which has fibres of 9 th n not aortic!!
Lemme know if am wrong
you are right!
it is the carotid sinus which senses the change through 9th Nerve
edited by Kurma on 12/4/2012
agrover1984 wrote:
devikabhatt wrote:
go back to the Anatomy of Sympathetic and Parasympathetic.This is a physiology question with anatomy basics.As far as I remember the aortic arch or aortic sinus is supplied by vagus nerve which is predominantly parasympathetic.
I think it's the carotid sinus which has fibres of 9 th n not aortic!!
Lemme know if am wrong
you are not wrong but I am also right.Transverse aotic arch and carotid sinus both have baroreceptors.The aortic arch baroreceptor signal is through vagus and carotid sinus baroreceptor through glossophryngeal.For details open the Guyton-a textbook of physiology or you can read on wikepedia.
edited by devikabhatt on 12/4/2012
Kurma wrote:
you are right!
it is the carotid sinus which senses the change through 9th Nerve
edited by Kurma on 12/4/2012
you are not wrong but I am also right.Transverse aotic arch and carotid sinus both have baroreceptors.The aortic arch baroreceptor signal is through vagus and carotid sinus baroreceptor through glossophryngeal.For details open the Guyton-a textbook of physiology or you can read on wikepedia.
edited by devikabhatt on 12/4/2012
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