<prompt> What are the types of cells present in coical collecting duct?Both Principal P cells Intercalated I cells.Only P cellsOnly I cellsNo cellular content  <response>: Both Principal P cells Intercalated I cells.Cells involved in reabsorption in coical collecting duct:Principal P cells.Intercalated I cells.FUNCTIONS OF P CELLS:1. Sodium water reabsorption:Reabsorbed from lumen.Occurs through Na2 channels ENaC channels. Approximately 3 Na reabsorption occurs.2. Potassium secretion:Secreted into lumen.K both secreted reabsorbed.Note: Na2 reabsorption K secretion depends on,Na2-K-ATPase activity in basolateral membrane.Aldosterone.3. Water reabsorption:ADH Controlled.Stimulates water channel, aquaporin-2.FUNCTIONS OF I CELLS:Reabsorb potassium ion.Secrete hydrogen ions into tubular lumen. 