part_of part of part of has_part has part has part deep to superficial to composed primarily of immediate transformation of material entity elastic fiber skin epidermis dermis http://upload.wikimedia.org/wikipedia/commons/2/23/EpidermisPainted.svg AAO:0000128 XAO:0000217 BTO:0000294 MIAA:0000153 FMA:70323 corium uberon EMAPA:17527 EFO:0000953 MAT:0000153 When approaching controversies surrounding skin evolution, we need to remember that the skin consists of two layers, an epidermis and a dermis, not a single evolving structure. (...) It is little wonder that controversies about homology exist. If we think of the epidermis, the dermis, and their interactions as an evolving unit, then their specialized products (hair, feathers, and reptilian scales) are broadly homologous.[well established][VHOG] MESH:D020405 GAID:1321 Consider adding a layer-of-skin grouping class for all skin layers A collagenous layer of the skin subjacent to the epidermis and covering the hypodermis. It contains various types of cells (e.g. fibroblasts, pigment cells, nerve, blood vessels and scales. Le Guellec et al, 2004.[TAO] ZFA:0001119 TAO:0001119 UBERON:0002067 cutis EV:0100154 MA:0000152 The dermis is a layer of skin between the epidermis (with which it makes up the skin) and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis[WP]. CALOHA:TS-2076 NCIT:C12701 vertebrate dermis VHOG:0000108 UMLS:C0011646 dermal SCTID:361696001 Wikipedia:Dermis hypodermis skin of body connective tissue future dermis structure with developmental contribution from neural crest collection of collagen fibrils integumentary system layer