In human anatomy, the mouth is the first portion of the alimentary canal that receives Human food and produces saliva.
In addition to its primary role as the beginning of the digestive system, the mouth also plays a significant role in communication. While primary aspects of the voice are produced in the throat, the tongue, , and human mandible are also needed to produce the range of sounds included in speech.
The mouth consists of two regions, the vestibule and the oral cavity proper. The mouth, normally moist, is lined with a mucous membrane, and contains the human teeth. The lips mark the transition from mucous membrane to human skin, which covers most of the human body.
Structure
Oral cavity
The mouth consists of two regions: the vestibule and the oral cavity proper. The vestibule is the area between the teeth, lips and cheeks.
The oral cavity is bounded at the sides and in front by the
alveolar process (containing the
human teeth) and at the back by the isthmus of the fauces. Its roof is formed by the
hard palate. The floor is formed by the
and is occupied mainly by the anterior two-thirds of the
tongue. A
mucous membrane – the
oral mucosa, lines the sides and under surface of the tongue to the
gingiva, and lines the inner aspect of the jaw (
human mandible). It receives secretions from the submandibular and
sublingual gland . The posterior border of the oral cavity (ie, junction between the oral cavity and the
oropharynx) includes the junction of the
hard palate and the
soft palate superiorly, the circumvallate papillae of the
tongue inferiorly, and the retromolar trigone.
Lips
The
come together to close the opening of the mouth, forming a line between the upper and lower lip. In facial expression, this
mouth line is iconically shaped like an up-open
parabola in a
smile, and like a down-open parabola in a
frown. A
down-turned mouth means a mouth line forming a down-turned parabola, and when permanent can be normal. Also, a
down-turned mouth can be part of the presentation of Prader–Willi syndrome.
Nerve supply
The teeth and the
periodontium (the tissues that support the teeth) are innervated by the
maxillary nerve and
– divisions of the
trigeminal nerve. Maxillary (upper) teeth and their associated periodontal ligament are innervated by the superior alveolar nerves, branches of the maxillary division, termed the posterior superior alveolar nerve, anterior superior alveolar nerve, and the variably present middle superior alveolar nerve. These nerves form the superior dental plexus above the maxillary teeth. The mandibular (lower) teeth and their associated periodontal ligament are innervated by the inferior alveolar nerve, a branch of the mandibular division. This nerve runs inside the mandible, within the
mandibular canal below the mandibular teeth, giving off branches to all the lower teeth (inferior dental plexus).
The
oral mucosa of the gingiva (gums) on the facial (labial) aspect of the maxillary
,
canine tooth and
premolar teeth is innervated by the superior labial branches of the infraorbital nerve. The posterior superior alveolar nerve supplies the gingiva on the facial aspect of the maxillary molar teeth. The gingiva on the
palate aspect of the maxillary teeth is innervated by the greater palatine nerve apart from in the incisor region, where it is the nasopalatine nerve (long sphenopalatine nerve). The gingiva of the
tongue aspect of the mandibular teeth is innervated by the sublingual nerve, a branch of the
lingual nerve. The gingiva on the facial aspect of the mandibular incisors and canines is innervated by the
mental nerve, the continuation of the inferior alveolar nerve emerging from the
mental foramen. The gingiva of the buccal (cheek) aspect of the mandibular molar teeth is innervated by the
buccal nerve (long buccal nerve).
Development
The
philtrum is the vertical depression formed between the
philtral ridges between the upper lip and the nasal septum, formed where the
nasomedial and
processes meet during embryo development. When these processes fail to fuse fully, a
cleft lip,
cleft palate, or both can result.
The are the deep creases of tissue that extend from the nose to the sides of the mouth. One of the first signs of age on the human face is the increase in prominence of the nasolabial folds.
Function
The mouth plays an important role in
eating,
, and speaking.
Mouth breathing refers to the act of breathing through the mouth (as a temporary backup system) if there is an obstruction to breathing through the nose, which is the designated breathing organ for the human body.
are born with a sucking reflex, by which they know to suck for nourishment using their lips and jaw.
The mouth also helps in chewing and biting food.
For some disabled people, especially many disabled artists, who through illness, accident or congenital disability have lost dexterity, their mouths take the place of their hands, when typing, texting, writing, making , and other works of art by maneuvering brushes and other tools, in addition to the basic oral functions. Mouth painters hold the brush in their mouth or between their teeth and maneuver it with their tongue and cheek muscles, but mouth painting can be strenuous for neck and jaw muscles since the head has to perform the same back and forth movement as a hand does when painting.
A male mouth can hold, on average, , while a female mouth holds .
See also
-
Head and neck anatomy
-
Index of oral health and dental articles
-
List of basic dentistry topics
-
Mouth breathing
Further reading
External links
