Download The cheeks, tongue, hard palate, and soft palate frame the mouth

Mouth
The cheeks, tongue, hard palate, and soft palate frame the mouth, also
called the oral cavity or buccal cavity. The mouth is involved in
both mechanical and chemical digestion. Mechanical digestion consists
of mastication (chewing), in which the tongue manipulates food, the
teeth grind it, and saliva mixes with it. Mastication turns food into an
easy-to-swallow bolus and breaks the food into smaller pieces so that
there is more contact area for digestive enzymes.
The cheeks make up the oral cavity's lateral walls. The outer covering of
the cheeks is the skin, and the inner covering is the mucous membrane.
This membrane is made up of nonkeratinized-stratified squamous
epithelium; the multiple layers are resistant to abrasion. Between the
skin and mucous membranes are connective tissue, fat tissue and
buccinator muscles.
The
bounds of the oral cavity. This work by Cenveo is licensed under a Creative Commons Attribution 3.0 United
States (http://creativecommons.org/licenses/by/3.0/us/).
The lips, also called labia ("fleshy borders"), encircle the opening of the
mouth. Their outer covering is skin, and their inner lining is mucous
membrane. Between these two layers is the orbicularis oris muscle.
Thelabial frenulum is a midline fold of mucous membrane that
attaches the inner surface of each lip to the gum. When we chew food,
the buccinator muscles in the cheeks and the orbicularis oris muscle in
the lips contract, which keeps food between the lower and upper teeth.
These muscles also play a role in speech.
The area between the lips (or cheeks) and teeth is called the oral
vestibule. The oral cavity is the area than runs between the gums
and teeth and the entrance to the throat (oropharynx), also called
the fauces ("passages"). If you puff out your cheeks, you can increase
the size of the oral vestibule but not the oral cavity.
The septum that separates the oral cavity and nasal cavity is called the
palate. Anatomically, a septum (plural, septa) is a wall within a single
organ or cavity that separates the space into distinct sides. For example,
the nasal septum divides the nostrils. This is separating two distinct
cavities.
Structures of the oral cavity. This work by Cenveo is licensed under a Creative Commons Attribution 3.0
United States (http://creativecommons.org/licenses/by/3.0/us/).
The palate, which forms the roof of the mouth, is what allows us to
breathe while chewing food. The anterior part of the roof of the mouth is
called the hard palate. It is created by the maxillae and palatine bones
and is covered by mucous membrane. The hard palate makes up the
bony wall between the oral and nasal cavities. The posterior part of the
roof of the mouth, the soft palate, is also lined with mucous
membrane. This arch-shaped muscular structure forms a dividing wall
between the oropharynx and nasopharynx.
The uvula (Latin for ‘little grape’) is a cone-shaped muscular process
that hangs from the end of the soft palate. It plays a role in speech and
articulation of words. It also plays a small role in preventing foods and
liquids from entering the nasal cavity. Two muscular folds on each side
of the base of the uvula extend down the lateral sides of the soft palate.
The anterior fold is called the palatoglossal arch, which terminates
next to the base of the tongue. The posterior fold,
the palatopharyngeal arch, lies at the interface with the pharynx.
Between these two arches on the lateral wall are the palatine tonsils.
The lingual tonsilsare located at the base of the tongue.
There are also many small, intrinsic salivary glands within the mucous
membrane of the mouth and tongue. Their secretion is independent of
the presence of food. These glands either open directly into the oral
cavity or indirectly through short ducts. The labial glands in the lips, the
buccal glands in the cheeks, the palatal glands in the palate, and the
lingual glands in the tongue secrete small amounts of saliva.