Countercurrent multiplication may not explain the axial osmolality gradient in the outer medulla of the rat kidney.

ABSTRACT: It has become widely accepted that the osmolality gradient along the corticomedullary axis of the mammalian outer medulla is generated and sustained by a process of countercurrent multiplication: active NaCl absorption from thick ascending limbs is coupled with the counterflow configuration of the descending and ascending limbs of the loops of Henle to generate an axial osmolality gradient along the outer medulla. However, aspects of anatomic structure (e.g., the physical separation of the descending limbs of short loops of Henle from contiguous ascending limbs), recent physiologic experiments (e.g., those that suggest that the thin descending limbs of short loops of Henle have a low osmotic water permeability), and mathematical modeling studies (e.g., those that predict that water-permeab

SUBMITTER: Layton AT 

PROVIDER: S-EPMC3213902 | biostudies-literature | 2011 Nov

REPOSITORIES: biostudies-literature