Concept of peripheral chemoreceptors - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
Home
USMLE Articles
USMLE News
USMLE Polls
USMLE Books
USMLE Apps
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 01-27-2012
USMLE Forums Veteran
 
Steps History: Not yet
Posts: 270
Threads: 34
Thanked 224 Times in 119 Posts
Reputation: 234
Question Concept of peripheral chemoreceptors

Peripheral Chemoreceptors:

Decrease TPR when decreased Pc02. Increased TPR when increased Pc02.

Can someone explain why?
When there is too much Pc02 shouldn't the body vasodilate to get rid of it? Similarly when there is not enough Pc02 shouldn't the body vasoconstrict to conserve it?
Reply With Quote Quick reply to this message



  #2  
Old 01-28-2012
USMLE Forums Veteran
 
Steps History: Not yet
Posts: 270
Threads: 34
Thanked 224 Times in 119 Posts
Reputation: 234
Default

anyone????
Reply With Quote Quick reply to this message
  #3  
Old 01-28-2012
USMLE Forums Scout
 
Steps History: ---
Posts: 58
Threads: 1
Thanked 141 Times in 19 Posts
Reputation: 151
Default

What are you talking about?

Chemoreceptors send signals for ventilation, they don't act on vasomotor tone!!!
Reply With Quote Quick reply to this message
 
  #4  
Old 01-28-2012
USMLE Forums Master
 
Steps History: 1+CK+CS
Posts: 646
Threads: 52
Thanked 762 Times in 256 Posts
Reputation: 773
Default

Quote:
Originally Posted by haga View Post
Peripheral Chemoreceptors:


When there is too much Pc02 shouldn't the body vasodilate to get rid of it? Similarly when there is not enough Pc02 shouldn't the body vasoconstrict to conserve it?
when there is too much PCO2 there is LESS O2....
if you DILATE....ur peripheral muscles etc are going to extract all that O2.. n then ur brain n heart (vital organs) already under stress will not hv any left!! hence you constrict periherally and dilate in ur brain.

if there is LESS PCO2... there is MORE O2...
hence you dilate in the periphery..

but ur brain thinks it has enough O2.... hence it constricts its vessels... (cos you know.. supply is enough.. why waste it lol!).. this results in decreased blood flow n u faint... THE CONCEPT OF HYPERVENTILATION LEADING TO FAINTING


remember what goljan says in his audios... CO2 AND O2 are both bound to Hb.. at the same sites.,... its an inverse relation!

Last edited by mbbs2010; 01-28-2012 at 06:29 AM.
Reply With Quote Quick reply to this message
The above post was thanked by:
krazzyrj (12-05-2015)
  #5  
Old 01-28-2012
USMLE Forums Master
 
Steps History: 1+CK+CS
Posts: 646
Threads: 52
Thanked 762 Times in 256 Posts
Reputation: 773
Default

oh n central chemoreceptors respond to CO2 levels...
peripheral respond to a low O2 level

however in COPD... when u hv chronic high CO2 levels.. they get accustomed to it.. hence the main drive for respiration becomes peripheral receptors.. that respond only to the low O2 level...
hence if u give a pt with COPD... 100% O2... the patient dies.. cos the drive for peripheral receptors... (which is DECREASED O2) is lost.
Reply With Quote Quick reply to this message
The above post was thanked by:
step_enhancer (01-28-2012)



Reply

Tags
Cardiovascular-, Nervous-System-, Physiology-

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
Where you live. Leave blank if you don't want to tell.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Peripheral nerve injury without numbness! USMLE-Syndrome USMLE Step 1 Forum 4 11-25-2011 01:30 PM
Endocarditis and peripheral embolization! m82_ghasemi USMLE Step 1 Forum 8 09-24-2011 09:55 PM
CCS:Infected peripheral IV access meduploader USMLE Step 3 Forum 0 09-22-2011 05:27 AM
peripheral capillary vasoconstriction chienpolska USMLE Step 1 Forum 0 08-18-2011 09:11 PM
Anemic Peripheral Smear! doctorF USMLE Step 1 Forum 16 05-31-2011 08:29 AM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)