Oral cavity

The entrance to the oral cavity (cavum oris) is the oral slit (rima oris). The oral cavity is bounded by the following structures: The furrows arise from the original embryonic two paired projections and one unpaired frontal projection → formation of the maxilla and filter in the middle. The projections fuse and thus give rise to the hard palate.Developmental anomalies may occur:
 * labium superius et inferius (upper and lower lip; their transition = angulus oris).
 * Grooves:
 * sulcus nasolabialis;
 * philtrum;
 * sulcus mentolabialis.


 * this creates communication between the upper and lower floors, the child cannot suck milk, has breathing problems and, at a later age, difficulties with articulation;
 * hereditary disorder;
 * deals with plastic surgery;
 * cleft of the lower jaw (symphysis menti does not develop) is not so common, rather the bone base is completely missing (only muscles develop).

Vestibulum oris
It is bounded by the face, lips and dental arches.
 * gingiva = gum;
 * glandula parotis (mouth at the 2nd uppermolar – ductus parotideus on the parotid papilla).

Cavitas oris propria

 * Practically entirely filled with tongue.

Hard palate (palatum durum)

 * Praemaxilla, proc. palatinus maxillae, lamina horizontalis ossis palatini;
 * connective: val = torus palatinus;
 * all covered with a soft palate.

Soft palate (palatum molle)

 * Rostral: mucosa, ligament, blood vessels, nerves.
 * Dorsally:
 * m. tensor veli palatini;
 * wraps around the hamulus pterygoideus;
 * acts as a pulley through which the muscle stretches the soft palate;
 * inenrvation: n. trigeminus (n. V);
 * m. levator veli palatini;
 * it attaches to the aponeurotic plate of the tensor;
 * helps raise the soft palate;
 * innervation:n. vagus (n. X);
 * m. palatopharyngeus;
 * expansion of the soft palate;
 * innervation:n. vagus (n. X);
 * m. palatoglossus;
 * expansion of the soft palate;
 * innervation:n. vagus (n. X);
 * m. uvulae;
 * innervation:n. vagus (n. X).

Functions of the soft palate:
 * 1) fonation;
 * 2) the septum between nasopharynx and the rest of the alimentary canal when swallowing;
 * 3) somatosensory function  (swallowing reflex).

Oral function
The oral cavity is the place of first contact of the digestive system with the ingested food. It includes specialized organs (tongue, teeth, salivary glands, etc.), that participate not only in processing food, but can also participate in other processes, such as the production of sounds. We can therefore describe the oral cavity as a very multifunctional space, which is particularly involved in:


 * 1)  Mechanical grinding of food using the teeth and tongue.
 * 2)  Wetting the bite with saliva and thus facilitating its passage to other parts of the GIT.
 * 3)  Initiation of digestive processes. The α-amylase contained in saliva is involved in the breakdown of starches.
 * 4)  Perception of taste and quality of food using different types of receptors (taste receptors[[, [[mechanoreceptors, thermoreceptors).
 * 5) Signaling to the distal parts of the GIT by coupling the lingual enteric system (LENS) and the enteric nervous system (ENS).
 * 6)   Defensive reflexes that prevent swallowing a bite.
 * 7)  Immune defense against infectious agents. Lysozyme, lactoferrin and IgA antibodies contained in saliva eliminate bacterial or viral infections in particular.
 * 8)  Speaking (articulation).
 * 9)  Breathing in case of increased ventilation.

Suction
is the primary form of food intake. The contraction of the muscles of the lips together with the movement of the tongue creates a negative pressure by which the food is sucked into the oral cavity. At a certain level, the bite is swallowed and the suction is repeated. The sucking reflex in infants is one of the unconditioned reflexes. In the course of life, it becomes a conditioned reflex and in the final stage it is a voluntary activity. If it appears during life at a stage other than infancy, it is usually a CNS pathology.

Chewing (masticatio)
is a rhythmic automatism, sometimes referred to as the masticatory reflex. These are stereotypically repeated movements that lead to grinding food and mixing it with saliva, which facilitates swallowing and subsequent digestive processes. The chewing control center is located in the brainstemand receives afferent mainly from the frontal and temporal parts of the cerebral cortex. The reflex action itself is initiated by mechanical irritation of the oral cavity with a bite. There is a relaxation of the tone of the masticatory muscles and a drop of the lower jaw (stretching of the masticatory muscles). A classic monosynaptic reflex follows = the stretched muscle contracts and the bite is pressed against the surface of the teeth and oral cavity. The reflex action is repeated several times with a frequency of 1.2 - 1.4 Hz.

Related articles

 * Tongue
 * Teeth
 * Facial clefts