Potassium shift and osmolarity! - 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 10-30-2011
USMLE Forums Veteran
 
Steps History: 1+CK+CS
Posts: 207
Threads: 68
Thanked 84 Times in 56 Posts
Reputation: 94
Kidney Potassium shift and osmolarity!

Can somebody help me explain the reason of why potassium shifts out of cell while surrounding is hyperosmolarity and shifting into cell in hypo-osmolarity?

Thanks a lot!
Reply With Quote Quick reply to this message



  #2  
Old 10-30-2011
USMLE Forums Addict
 
Steps History: Not yet
Posts: 141
Threads: 34
Thanked 32 Times in 24 Posts
Reputation: 42
Default A little more specific plz

This is a very broad question.
Can you be a little specific? Are you talking about a specific part of the tubule where K+ goes in and out of the cell?Or are you talking about any cell in general?
Reply With Quote Quick reply to this message
  #3  
Old 10-30-2011
USMLE Forums Veteran
 
Steps History: 1+CK+CS
Posts: 207
Threads: 68
Thanked 84 Times in 56 Posts
Reputation: 94
Default

Quote:
Originally Posted by docji View Post
This is a very broad question.
Can you be a little specific? Are you talking about a specific part of the tubule where K+ goes in and out of the cell?Or are you talking about any cell in general?
I'm not sure if it is focal or systematic. Maybe it is just talking about the transportation in specific region of renal tubule. Or it could be in a general picture. If it is just related to renal tubule system, how to explain the phenomenon? It's mentioned in FA2011, page464.
Reply With Quote Quick reply to this message
  #4  
Old 10-30-2011
USMLE Forums Scout
 
Steps History: 1+CK+CS
Posts: 29
Threads: 3
Thanked 21 Times in 9 Posts
Reputation: 31
Default

Not sure how but Increased osmolarity as seen in dka n hhs are due to an absolute or relative deficiency in insulin which is needed to drive k+ into cells
Reply With Quote Quick reply to this message
The above post was thanked by:
belindalimm (10-30-2011)
  #5  
Old 10-30-2011
USMLE Forums Addict
 
Steps History: Not yet
Posts: 141
Threads: 34
Thanked 32 Times in 24 Posts
Reputation: 42
Default ...

Quote:
Originally Posted by belindalimm View Post
I'm not sure if it is focal or systematic. Maybe it is just talking about the transportation in specific region of renal tubule. Or it could be in a general picture. If it is just related to renal tubule system, how to explain the phenomenon? It's mentioned in FA2011, page464.
my friend,
these are the things that lead to hyperkalemia. You asked the wrong question:
On pg 464, they are mentioning the 6 reasons that will lead to Hyperkalemia.
And of course, hyperosmalarity, cell lysis, acidosis, insulin def, etc will lead to increase K+ in the plasma leading to Hyperkalemia.
Its not saying that K+ shifts out of cell during Hyperosmality. Thats ridiculous lol. Your concepts are right, but u understood it wrong.

no worries though... it happens to all of us all the time.
Reply With Quote Quick reply to this message
  #6  
Old 10-31-2011
USMLE Forums Scout
 
Steps History: 1+CK+CS
Posts: 29
Threads: 3
Thanked 21 Times in 9 Posts
Reputation: 31
Default

Quote:
Originally Posted by docji View Post
my friend,
these are the things that lead to hyperkalemia. You asked the wrong question:
On pg 464, they are mentioning the 6 reasons that will lead to Hyperkalemia.
And ofcourse, hyperosmalarity, cell lysis, acidosis, insulin def, etc will lead to increase K+ in the plasma leading to Hyperkalemia.
Its not saying that K+ shifts out of cell during Hyperosmality. Thats ridiculous lol. Your concepts are right, but u understood it wrong.

no worries though... it happens to all of us all the time.
Im sorry I dont agree with you and neither does BRS physiology. Table on page 167 shows causes of shifts of K+ out of cells and hyperosmolarity is one of them (says that H2O flows out of the cell n K+ diffuses out with it). I guess that's settled then.
Reply With Quote Quick reply to this message
The above post was thanked by:
astrocarter15 (01-03-2015), belindalimm (10-31-2011)
  #7  
Old 10-31-2011
USMLE Forums Addict
 
Steps History: Not yet
Posts: 141
Threads: 34
Thanked 32 Times in 24 Posts
Reputation: 42
Default so wats the answer

Quote:
Originally Posted by olsmade View Post
Im sorry I dont agree with you and neither does BRS physiology. Table on page 167 shows causes of shifts of K+ out of cells and hyperosmolarity is one of them (says that H2O flows out of the cell n K+ diffuses out with it). I guess that's settled then.
ye may be i understood it wrong.
"I guess its settled"... whats settled? wats the answer?
Reply With Quote Quick reply to this message
  #8  
Old 10-31-2011
USMLE Forums Addict
 
Steps History: Not yet
Posts: 141
Threads: 34
Thanked 32 Times in 24 Posts
Reputation: 42
Default ..

While studying renal I remember that in the lumen K+, Cl- and Na+ can easiely diffuse transcellularly (through cells) and paracellularly (between cells) with water, since they are dissolved in it.
The transport mechanisms, which require receptors, for larger molecules like glucose, amino acids, HCO3-, etc concentrate the lumen and get transported to say PCT cells. PCT cells via facilitated diffusion pump them out to ISF. If their conc increases there then more water gets pulled out from the tubes to the ISF and it drags the K+ along with it.
Reply With Quote Quick reply to this message
  #9  
Old 10-31-2011
USMLE Forums Veteran
 
Steps History: 1+CK+CS
Posts: 207
Threads: 68
Thanked 84 Times in 56 Posts
Reputation: 94
Default

Quote:
Originally Posted by docji View Post
my friend,
these are the things that lead to hyperkalemia. You asked the wrong question:
On pg 464, they are mentioning the 6 reasons that will lead to Hyperkalemia.
And ofcourse, hyperosmalarity, cell lysis, acidosis, insulin def, etc will lead to increase K+ in the plasma leading to Hyperkalemia.
Its not saying that K+ shifts out of cell during Hyperosmality. Thats ridiculous lol. Your concepts are right, but u understood it wrong.

no worries though... it happens to all of us all the time.
Hi, I see it mentions six causes that lead to hyperkalemia but for development of hyperkalemia potassium is required to move out of cells and into plasma to generate high concentration. So my understanding of the interpretation about the materials in FA is during hyperosmolarity potassium moves out and into plasma. But don't know the exact reason. I agree with the opinion mentioning K+ moves out with water in hyperosmolarity.
Reply With Quote Quick reply to this message
  #10  
Old 01-27-2012
USMLE Forums Scout
 
Steps History: Step 1 Only
Posts: 73
Threads: 10
Thanked 7 Times in 4 Posts
Reputation: 17
Default

Quote:
Originally Posted by olsmade View Post
Not sure how but Increased osmolarity as seen in dka n hhs are due to an absolute or relative deficiency in insulin which is needed to drive k+ into cells
so far as i know, in DKA there is increased H+ which draws K+ out of the cell and H+ inters into cells as cell surface contains H+/K+ pump, so hyperkalaemia occurs in DKH
Reply With Quote Quick reply to this message



Reply

Tags
Electrolytes-, Physiology-, Renal-

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
Potassium Insulin Relationship Ahmed-USMLE USMLE Step 1 Bits & Pieces 14 08-08-2016 12:27 PM
Pneumothorax: mediastinal shift away or towards prim USMLE Step 1 Forum 5 01-13-2011 01:46 PM
DKA and Potassium Level hippocampus USMLE Step 1 Forum 13 07-16-2010 09:27 AM
Plasma osmolarity vs urine sodium level lemontea88 USMLE Step 1 Forum 5 06-17-2010 10:09 PM
ADH Sensitivity to volume and osmolarity Firas USMLE Step 1 Forum 6 12-18-2009 12:18 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)