Talk:Countercurrent multiplication

Permeabilities to water.
I think the following, under the headline Details - pump, might be wrong: "The thick ascending limb of the loop of Henle is the only part of the nephron lacking in aquaporin - a common transporter protein for water channels."

To my knowledge, the thin ascending loop of Henle is also impermeable to water. It also says so earlier (though not explicitly for both segments of the ascending limb) in the article, under the headline physiological principles: "The ascending limb is impermeable to water".

source: Walter F. Boron, Emile L. Boulpaep, Medical physiology, 2nd edition. — Preceding unsigned comment added by 83.91.89.186 (talk) 21:29, 13 November 2012 (UTC)
 * Agreed.Cpsoper (talk)

Birds
Have removed statement about birds having a different mechanism for concentrating urine. They have a hybrid system, but concentration appears to depend wholly on nephrons with mammalian characteristics. Accessible abstract ref added.Cpsoper (talk) 05:22, 14 June 2014 (UTC)