title: Structural organization of the renal medullary counterflow system.
abstract: The microscopic structure of the various nephron segments comprising the medullary counterflow system is described. The architectural organization of the tubules and blood vessels in the inner and outer medulla is also described. Species differences are noted. A hypothesis that the thicker parts of the descending limbs of Henle actively secrete salt is advanced.
mesh_terms: D000818:Animals; D007671:Kidney Concentrating Ability; D007679:Kidney Medulla / Q000033:anatomy & histology* / Q000098:blood supply; D007685:Kidney Tubules, Collecting / Q000033:anatomy & histology; D007686:Kidney Tubules, Distal / Q000033:anatomy & histology; D007687:Kidney Tubules, Proximal / Q000033:anatomy & histology; D008138:Loop of Henle / Q000033:anatomy & histology; D012377:Rodentia