Stomodeum 4782087 209257021 2008-04-30T16:33:46Z 151.112.37.162 {{Infobox Embryology | Name = {{PAGENAME}} | Latin = | GraySubject = 241 | GrayPage = 1101 | Image = Gray977.png | Caption = Human embryo about fifteen days old. [[Brain]] and [[heart]] represented from right side. [[Digestive tube]] and [[yolk sac]] in median section. (Stomodeum labeled in upper right.) | Image2 = | Caption2 = | System = | CarnegieStage = 9 | Precursor = [[surface ectoderm]] | GivesRiseTo = | MeshName = | MeshNumber = | DorlandsPre = s_24 | DorlandsSuf = 12760230 | }} The '''stomodeum''', also called '''stomatodeum''', is a depression between the [[brain]] and the [[pericardium]] in an [[embryo]], and is the precursor of the [[mouth]] and the anterior lobe of the [[pituitary gland]]. ==Structure== The stomodeum is lined by [[ectoderm]], and is separated from the anterior end of the [[fore-gut]] by the buccopharyngeal membrane. This membrane is devoid of [[mesoderm]], being formed by the apposition of the stomodeal ectoderm with the fore-gut endoderm; at the end of the third week it disappears, and thus a communication is established between the mouth and the future [[pharynx]]. ==Development== The mouth is developed partly from the stomodeum, and partly from the floor of the anterior portion of the [[fore-gut]]. By the growth of the head end of the [[embryo]], and the formation of the [[cephalic flexure]], the [[pericardial area]] and the [[buccopharyngeal membrane]] come to lie on the ventral surface of the [[embryo]]. With the further expansion of the [[brain]], and the forward bulging of the [[pericardium]], the buccopharyngeal membrane is depressed between these two prominences. This depression constitutes the stomodeum. No trace of the membrane is found in the adult; and the communication just mentioned must not be confused with the permanent isthmus faucium. The [[lips]], [[teeth]], and [[gums]] are formed from the walls of the stomodeum, but the [[tongue]] is developed in the floor of the pharynx. ==Additional images== <gallery> Image:Gray40.png|Embryo between eighteen and twenty-one days. Image:Gray44.png|Under surface of the head of a human embryo about twenty-nine days old. Image:Gray45.png|Head end of human embryo of about thirty to thirty-one days. </gallery> ==External links== * [http://connection.lww.com/Products/sadler/images/figurelarge15-5.jpg Diagram at lww.com] * {{EmbryologyUNC|hednk|015a}} {{developmental-biology-stub}} {{Gray's}} {{Development of digestive system}} [[de:Stomodeum]][[sv:Stomodeum]][[Category:Embryology]]