Editing Collecting duct system (section)

====Medullary collecting duct==== <!--Medullary collecting duct redirects here-->
"Medullary collecting ducts" are divided into outer and inner segments, the latter reaching more deeply into the medulla. The variable reabsorption of water and, depending on fluid balances and hormonal influences, the reabsorption or secretion of sodium, potassium, hydrogen and bicarbonate ion continues here. Urea passively transports out of duct here and creates 500mOsm gradient.

{{anchor|Outer segment}}<!--Outer medullary collecting duct redirects here-->
The outer segment of the medullary collecting duct follows the cortical collecting duct. It reaches the level of the renal medulla where the [[thin descending limb of loop of Henle]] borders with the [[thick ascending limb of loop of Henle]]<ref>{{Cite book|last = Boron|first=Walter F.|title=Medical Physiology: A Cellular and Molecular Approach| edition = updated| publisher=Elsevier/Saunders|location=Philadelphia |year=2005 |isbn=1-4160-2328-3}}</ref>{{rp|837}}

{{anchor|Inner segment}} <!--Inner medullary collecting duct redirects here-->
The inner segment is the part of the collecting duct system between the outer segment and the papillary ducts.