part of part of has part develops from glandular secretory epithelial cell lysozyme secreting cell paneth cell An epithelial cell found in the basal part of the intestinal glands (crypts of Lieberkuhn) including the appendix. Paneth cells synthesize and secrete lysozyme and cryptdins. Numerous in the deeper parts of the intestinal crypts, particularly in the duodenum, rich in zinc, contain large acidophilic granules, with irregular apical microvilli and prominent membrane-bound vacuoles containing matrix. https://cellxgene.cziscience.com/cellguide/CL_0000510 BTO:0000993 FMA:62897 Paneth cells are specialized epithelial cells that are primarily located at the bottom of the crypts of Lieberkühn in the small intestine, where they play a pivotal role in maintaining gut homeostasis. They have also been found in smaller numbers in the colonic crypts and other parts of the gastrointestinal tract. Paneth cells are characterized by large acidophilic granules, which take up most of the cytoplasmic volume, causing the nucleus to be pushed toward the base of the cell. Paneth cells function as a part of the innate immune system. The large granules inside the cells are filled with antimicrobial peptides, such as defensins and lysozymes. Upon bacterial intrusion or cellular signaling indicating a potential infection, Paneth cells release the granules containing the antimicrobial substances into the crypt lumen, effectively serving as the first line of defense against bacterial invasion within the gastrointestinal tract. In essence, Paneth cells serve as guardians, protecting the intestinal stem cells from harmful pathogens that may disturb the gut ecosystem. In addition to their primary role in immunity, Paneth cells are also crucial for supporting the stem cell niche in the intestinal crypts. They are located adjacent to Lgr5+ stem cells and secrete various growth factors such as EGF, TGF-alpha, Wnt3, and Notch ligand Dll4. These factors regulate the self-renewal and differentiation of these stem cells, which continuously replenish the intestinal epithelium. Consequently, any abnormality or dysfunction in Paneth cells could lead to a disturbance in gut homeostasis, possibly resulting in various illnesses such as inflammatory bowel disease. (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.) intestinal epithelial cell transit amplifying cell of gut vacuole microvillus epithelium of crypt of Lieberkuhn