World Library  
Flag as Inappropriate
Email this Article

Selective reabsorption

Article Id: WHEBN0007412198
Reproduction Date:

Title: Selective reabsorption  
Author: World Heritage Encyclopedia
Language: English
Subject: Nephridium, Renal physiology
Publisher: World Heritage Encyclopedia

Selective reabsorption

A basic outline of the process of selective reabsorption

  • The co-transport pump actively transports sodium out of the PCT(Proximal Convoluted Tubule) wall (using energy from converting ATP to ADP + Pi) to maintain a low Na+ concentration gradient in the wall.
  • This low concentration gradient means that Na+ ions from the glomerulus filtrate can easily passively diffuse into the wall of the PCT.
  • However the Na+ ions cannot diffuse freely across the membrane, but can only enter through special transporter (carrier) proteins in the membrane of the wall.
  • There are several different kinds of these transporter proteins, each of which transports another molecule, such as glucose or amino acids. The concentration gradient for the sodium provides the energy to pull in these other molecules into the wall of the PCT.
  • As the substances listed above (Na+ ions, amino acids and glucose) enter the wall of the PCT, so does 65-70% of the water in the glomerulus filtrate via osmosis. Water can move freely through the wall of the PCT (it does not require a transporter protein.) Nearly all the rest of the water is reabsorbed into the blood in the Loop of Henle and the Collecting duct system.
  • However as urea is a small molecule it can pass easily through the membrane of the PCT wall. As the concentration of urea in the filtrate is significantly higher than in the blood, around 50% of urea on the filtrate is reabsorbed. biologi natrium
  • Natrium is a new element recently found by Noel Jackson and Mr McMarty.


  • Mr A.J.Yorath, M.C.S.
  • Kit Briant & Andrew Gove.
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.