The stomodeum, also called stomatodeum or stomatodaeum, is a depression between the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...

and the

pericardium The pericardium, also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong connective tissue (fibrous pericardium), and an inner layer made of ...

in an

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

, and is the precursor to the

mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...

and the anterior lobe of the

pituitary gland In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland, about the size of a chickpea and weighing, on average, in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The ...

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

, and the formation of the

cephalic flexure Three flexures form in the part of the embryonic neural tube that develops into the brain. At four weeks gestational age in the human embryo the neural tube has developed at the cranial end into three swellings – the primary brain vesicles. T ...

, the pericardial area and the

buccopharyngeal membrane The region where the crescentic masses of the ectoderm and endoderm come into direct contact with each other constitutes a thin membrane, the buccopharyngeal membrane (or oropharyngeal membrane), which forms a septum between the primitive mouth and ...

come to lie on the ventral surface of the

. With the further expansion of the

, and the forward bulging of the

, the

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

lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

, and

gums The gums or gingiva (plural: ''gingivae'') consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health. Structure The gums are part of the soft tissue linin ...

are formed from the walls of the stomodeum, but the

tongue The tongue is a muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper surfa ...

is developed in the floor of the pharynx.

History

It is from the Greek ''stoma-'' (mouth) and ''odaios'' (likeness), "which looks like a mouth".

Additional images

File:Gray40.png,

Embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

between eighteen and twenty-one days. File:Gray44.png, Under surface of the head of a human embryo about twenty-nine days old. File:Gray45.png, Head end of human embryo of about thirty to thirty-one days.

References

External links

Diagram at lww.com
* {{Authority control Embryology of digestive system