part of part of epithelial cell epidermal cell An epithelial cell of the integument (the outer layer of an organism). cell of epidermis https://cellxgene.cziscience.com/cellguide/CL_0000362 FMA:62411 BTO:0001470 ZFA:0009183 MESH:D000078404 Epidermal cells constitute the outermost layer of the skin in animals and have a multifaceted role in maintaining the body's overall homeostasis. They originate from the ectoderm and form the epidermis, a stratified squamous epithelium that mostly consists of keratinocytes in various stages of differentiation. The primary role of these cells is to act as a physical barrier, shielding the internal organs, tissues, and system from dehydration, infection, and other external influences such as UV radiation. The thickness and stratification of the epidermis vary with its location in the body, depending on the specific demand for protective function. One notable characteristic of epidermal cells is their continuous cycle of renewal. The cells are produced in the deepest layer of the epidermis, known as the basal or germinative layer, where they undergo cell division. As new cells form, they gradually push the older cells towards the skin surface. While ascending, these cells undergo a process known as keratinization, where they become filled with keratin, a protein that provides strength and rigidity. By the time they reach the surface, they are essentially dead and filled with keratin, forming a tough, resistant layer that is regularly shed and replaced by newer cells beneath. This entire process, from cell generation to shedding, usually takes around a month. (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.) CALOHA:TS-0283 epithelial cell of skin general ecto-epithelial cell outer epithelium