columnar/cuboidal epithelial cell meso-epithelial cell renal intercalated cell A cuboidal epithelial cell of the kidney that regulates acid/base balance. ZFA:0009375 Intercalated cells are also called “mitochondria-rich cells”, reflecting the high levels of round mitochondria at their apical pole, or in their cytoplasm, a distribution that is quite different from that of other kidney tubule cells, which accumulated mitochondria around the basolateral membrane. These cells also have numerous irregular apical microvilli compared with the surrounding segment-specific cells. Intercalated cells lack a central cilium, at least in the cortex, which also differentiates them from the adjacent principal cells. Renal intercalated cells are specialized cells located in the collecting duct system of the kidneys. The primary role of intercalated cells is to reabsorb bicarbonate ions and secrete hydrogen ions, thereby maintaining the acid-base homeostasis in the blood. They comprise two main subtypes primarily distinguished by their functional and morphological attributes: alpha and beta intercalated cells. Alpha intercalated cells are more predominant when the body is in a state of acidosis, a condition characterized by an increased acidity of the blood. These cells are specialized in secreting excessive hydrogen ions into the urine through a mechanism involving vacuolar H+-ATPase and H+/K+-ATPase pumps on their apical membranes. They simultaneously reabsorb bicarbonate ions from the tubular fluid and return them to the bloodstream via mechanisms involving carbonic anhydrase II and bicarbonate/chloride exchangers on the basolateral membrane. This dual process helps to increase blood pH towards normal levels. When the body is in a state of alkalosis, a condition characterized by lowered levels of hydrogen ions in the blood, beta intercalated cells are more predominant. They primarily reabsorb hydrogen ions from the tubular fluid through vacuolar H+-ATPase and H+/K+-ATPase pumps on their basolateral membranes, while secreting bicarbonate ions into the urine via pendrin, a bicarbonate/chloride exchanger in the apical membrane. These mechanisms work together to decrease blood pH towards normal levels. In summary, renal intercalated cells play a critical role in the delicate balance of the body’s pH, safeguarding the body from potential harm caused by acidemia or alkalemia. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) intercalated cell FMA:86560 epithelial cell of nephron