human_reference_atlas part of Homo sapiens epithelium tonsil palatine tonsil tonsil crypt NCIT:C33791 Tonsils consist of an extensive system of crypts, which result in a large internal surface. The tonsils contain four lymphoid compartments that influence immune functions, namely the reticular crypt epithelium, the extrafollicular area, the mantle zones of lymphoid follicles, and the follicular germinal centers. In human palatine tonsils, the very first part exposed to the outside environment is tonsillar epithelium. MA:0000777 UMLS:C0229876 AS Wikipedia:Tonsillar_crypts tonsillar crypt uberon tonsil crypt FMA:55044 UBERON:0012181 cryptae tonsillares SCTID:143723007 tonsil crypt