free and obligated water in urine.. - 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 07-31-2010
USMLE Forums Scout
 
Steps History: Not yet
Posts: 14
Threads: 4
Thanked 1 Time in 1 Post
Reputation: 11
Kidney free and obligated water in urine..

Medullary segment of thick ascending limb – where the Na/K-2Cl pump is – which is where loop diuretics block. The Na/K-2Cl pump generates free water. The two type of water in urine: obligated and free. If the water is obligated, then the water is obligated to go out with every Na, K, and Cl (concentrated urea). Basically 20 ml’s of obligated water for every Na, K, Cl (it’s obligated) via Na/K/2Cl pump. The ADH hormone absorbs free water b/c the pump generates free water.
Let’s say you absorb one Na, how much free water is left behind in the urine? – 20 mls; then reabsorbed another K, that is another 20, so its up to 40; another 2 Cl’s are reabsorbed which is another 40; therefore, for absorbing one Na, one K, and 2 Cl’s, you have taken 80 mls of free water from the urine – this is free water that is generated; its is this pump that loop diuretics block, which is in the thick ascending limb of the medullary segment.


this is what said told in goljan audio....but cant understand..if na-k-2 cl cotransport causes 80 ml of free water absorbed..but also said that ""
If the water is obligated, then the water is obligated to go out with every Na, K, and Cl (concentrated urea). Basically 20 ml’s of obligated water for every Na, K, Cl (it’s obligated) via Na/K/2Cl pump""
so whats true--na/k/2 cl cotranport associated with free water or obligated water..





Reply With Quote Quick reply to this message



  #2  
Old 07-31-2010
USMLE Forums Addict
 
Steps History: Not yet
Posts: 161
Threads: 60
Thanked 24 Times in 20 Posts
Reputation: 34
Send a message via Skype™ to Androide89
Default

ascending portion is impermeable to water so free water is produced not reabsorbed. If u block it with a loop then you're not producing that free water which could've been reabsorbed in the collecting ducts via ADH, hence diuresis occurs.
Reply With Quote Quick reply to this message
  #3  
Old 08-01-2010
USMLE Forums Scout
 
Steps History: 1 + CK
Posts: 88
Threads: 12
Thanked 177 Times in 49 Posts
Reputation: 187
Default free water...free from obligation

free water is generated from the water-impermeable medullary (Na/K/2cl) and cortical (Na/Cl) portions of the nephron.
20ml of water is obliged to be excreted with each Na etc.
But because of the action of these 2 pumps, Na, K ,Cl are absorbed , hence freeing that water from its obligation, i.e converts obligated water to free water, which can the be reabsorbed via ADH dependent mechanisms in the collecting tubule and duct.
Blocking these pumps, reduces free water, and increases obligated water which is passed out as diuresis.
Reply With Quote Quick reply to this message
 
  #4  
Old 08-01-2010
USMLE Forums Addict
 
Steps History: Not yet
Posts: 161
Threads: 60
Thanked 24 Times in 20 Posts
Reputation: 34
Send a message via Skype™ to Androide89
Default

Quote:
Originally Posted by tunde michael View Post
free water is generated from the water-impermeable medullary (Na/K/2cl) and cortical (Na/Cl) portions of the nephron.
20ml of water is obliged to be excreted with each Na etc.
But because of the action of these 2 pumps, Na, K ,Cl are absorbed , hence freeing that water from its obligation, i.e converts obligated water to free water, which can the be reabsorbed via ADH dependent mechanisms in the collecting tubule and duct.
Blocking these pumps, reduces free water, and increases obligated water which is passed out as diuresis.
blocking ADH pumps would increase free water not reduce.
Reply With Quote Quick reply to this message
  #5  
Old 08-03-2010
USMLE Forums Scout
 
Steps History: 1 + CK
Posts: 88
Threads: 12
Thanked 177 Times in 49 Posts
Reputation: 187
Default

Androide99,
by 'these pumps' in the last paragragh of my post, i meant Na/K/2Cl and Na/Cl pumps only.
Reply With Quote Quick reply to this message
  #6  
Old 03-21-2011
USMLE Forums Scout
 
Steps History: 1+CK+CS
Posts: 41
Threads: 19
Thanked 9 Times in 3 Posts
Reputation: 19
Send a message via Skype™ to laxitjn
Default

The Na/K-2Cl pump generates free water. the ascending limb is the diluting segment . Salt is extracted and a hypotonic fluid is left in the lumen which will pass thru unaffected . ADH makes the wall of the remaining portion of DCT and CD permeable to water , ensuring we absorb "free" water , without any Na , K ,Cl ,tied to it . The pump dissociates water movement with Ion movement .

The two type of water in urine: obligated and free. If the water is obligated, then the water is obligated to go out with every Na, K, and Cl (concentrated urea). Basically 20 mlís of obligated water for every Na, K, Cl (itís obligated) via Na/K/2Cl pump. The ADH hormone absorbs free water b/c the pump generates free water.

Letís say you absorb one Na, how much free water is left behind in the urine? Ė 20 mls; then reabsorbed another K, that is another 20, so its up to 40; another 2 Clís are reabsorbed which is another 40; therefore, for absorbing one Na, one K, and 2 Clís, you have taken 80 mls of free water from the urine Ė this is free water that is generated;


it is this pump that loop diuretics block, which is in the thick ascending limb of the medullary segment. So the ions remain in the lumen , binding the water with them , prevent absorption via ADH mediated increase in permeability and thus cause diuresis
Reply With Quote Quick reply to this message



Reply

Tags
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
USMLE Free Practice Materials (Free 150) Sabio General Topics Recommended Threads 6 04-18-2017 04:08 AM
Bubbles in Urine - Pneumaturia lee-usmle USMLE Step 2 CK Buzzwords 3 02-29-2012 09:26 AM
Tea Colored Urine FreakingOut USMLE Step 1 Forum 2 04-21-2010 08:23 AM
Water Deprivation Test? examinitis USMLE Step 2 CS Forum 1 01-17-2010 01:13 PM
Urine color changes by drugs aalous USMLE Step 1 Forum 1 11-20-2009 03:08 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)