This MedLibrary.org supplementary page on Stomodeum is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
| Stomodeum | ||
|---|---|---|
 |
||
| 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.) | ||
| Gray's | subject #241 1101 | |
| Carnegie stage | 9 | |
| Precursor | surface ectoderm | |
| Dorlands/Elsevier | s_24/12760230 | |
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.
Contents |
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
 Embryo between eighteen and twenty-one days. |
 Under surface of the head of a human embryo about twenty-nine days old. |
 Head end of human embryo of about thirty to thirty-one days. |
External links
 |
This developmental biology article is a stub. You can help Wikipedia by expanding it. |
This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
|
|||||||||||
Wikipedia content modification information:
- This page was last modified on 30 April 2008, at 16:33.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Stomodeum".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.