Editing Collecting duct system (section)

====Connecting tubule====
With respect to the [[renal corpuscle]], the '''connecting tubule''' ('''CNT''', or '''junctional tubule''', or '''arcuate renal tubule''') is the most proximal part of the collecting duct system. It is adjacent to the [[distal convoluted tubule]], the most distal segment of the [[renal tubule]]. Connecting tubules from several adjacent nephrons merge to form cortical collecting tubules, and these may join to form cortical collecting ducts (CCD).<ref>{{cite journal | author=Imai M | title=The connecting tubule: a functional subdivision of the rabbit distal nephron segments | journal=Kidney Int | year=1979 | pages=346–56 | volume=15 | issue=4 | pmid=513494 | doi=10.1038/ki.1979.46| doi-access=free }}</ref> Connecting tubules of some [[juxtamedullary nephron]]s may arch upward, forming an arcade. It is this "arcuate" feature which gives the tubule its alternate name.

The connecting tubule derives from the [[metanephric blastema]], but the rest of the system derives from the [[ureteric bud]].<ref>{{Cite book|last=Mitchell, B. S.|title=Embryology: an illustrated colour text|date=2009|publisher=Churchill Livingstone/Elsevier|others=Sharma, Ram, Britton, Robert.|isbn=978-0-7020-5081-7|edition=2nd|location=Edinburgh|pages=50–51|oclc=787843894}}</ref> Because of this, some sources group the connecting tubule as part of the [[nephron]], rather than grouping it with the collecting duct system.

{{anchor|Initial collecting tubule}}
The initial collecting tubule is a segment with a constitution similar as the collecting duct, but before the convergence with other tubules.

{{anchor|Cortical collecting duct}}
The "cortical collecting ducts" receive filtrate from multiple initial collecting tubules and descend into the [[renal medulla]] to form medullary collecting ducts.

It participates in the regulation of [[water]] and [[electrolyte]]s, including [[sodium]], and [[chloride]].<ref>{{cite book |author1=Eaton, Douglas C. |author2=Pooler, John P. | title=Vander's Renal Physiology | publisher=Lange Medical Books/McGraw-Hill | year=2004 | edition=6th | isbn=0-07-135728-9}}</ref> The CNT is sensitive to both [[isoprotenerol]] (more so than the cortical collecting ducts) and [[antidiuretic hormone]] (less so than the cortical collecting ducts), the latter largely determining its function in water reabsorption.