Oral organs and their functions. About the anatomy of the human oral cavity What is the oral cavity

AT oral cavity food is crushed, wetted with saliva, and then moved into the throat.

The organs of the oral cavity are: lips, cheeks, teeth, gums, hard and soft palate, tongue, tonsils and salivary glands. Its bone base is formed by the maxillary, mandibular, incisive and palatine bones. In the oral cavity, the vestibule and the oral cavity itself are distinguished. These parts are separated by teeth, incisors and gums. The vestibule of the mouth is in the form of a gap, bounded from the outside by the upper and lower lips and cheeks, and from the inside by two rows of teeth. The edges of the lips limit the inlet - the oral fissure. Actually, the oral cavity is limited in front and on the sides by the gums and teeth, above and behind - by the hard and soft palate, from below - by the bottom of the oral cavity with the tongue.

Lips consist of skin, muscle layer and mucous membrane.

The skin covers the lips from the outer surface. Under the skin lies a closely fused neuromuscular layer. The inner layer of the lips is the mucous membrane. The submucosal connective tissue contains the labial glands. The mucous membrane of the lips, as well as the entire oral cavity, is covered with squamous stratified epithelium. On the free edge of the lips, it turns into a general skin covering. The lower lip continues into the chin.

At horses, sheep and goats lips strongly developed and easily mobile in all areas. In the middle, a labial groove is clearly visible (less marked in a horse).

Lips cattle thick and immobile. The upper lip passes into the nasolabial mirror, devoid of hair. The mucous membrane of the lateral parts of the lips forms high cone-shaped papillae.

Lips pigs short and immobile. The upper lip merges with the proboscis, the lower one becomes sharper.

At dogsupper lip with a deep narrow groove and passes into the nasal mirror.

The cheeks form the side walls of the oral cavity. They consist of skin, muscle, glandular layer and mucous membrane. The buccal glands are divided into upper and lower. Cattle also have middle buccal glands. The mucous membrane of the cheeks forms cone-shaped papillae.

The gums are a mucous membrane that covers the alveolar processes of the jaws and incisors, surrounds the necks of the teeth and is closely fused with the periosteum. In ruminants, in place of the upper incisor teeth, the gum forms a thickening - a dental plate covered with a thick keratinizing epithelium.

Solid sky serves as the vault of the oral cavity and is formed by a thick, hard mucous membrane covering the bony palate. Aborally, it passes into the soft palate, or palatine curtain, and from the sides - into the gums. A palatine suture runs along the midline of the hard palate, on both sides of which on the hard palate there are transverse thickenings of the mucous membrane - palatine ridges - in the form of arcuate folds. At the anterior end of the palatine suture, directly behind the incisive teeth, the palatine, or incisive, papilla rises (the horse does not have it), on the sides of which in nasal cavity thin nasolacrimal ducts open.

In the submucosal tissue of the hard palate there is a dense plexus of venous vessels.

Soft sky, or palate curtain, is a continuation of the hard palate. It is a fold of the mucous membrane with muscles, glands, lymph nodes embedded in it and separates the oral cavity from the pharyngeal cavity. Between the free edge of the palatine curtain and the root of the tongue, an opening is formed leading from the oral cavity to the pharyngeal cavity. This is the gap of the pharynx. At horses the palatine curtain is very long, reaching the root of the tongue, and therefore the possibility of breathing through the mouth is excluded. Other animal species have a shorter palate and can breathe through their mouths.

The palatine curtain has two surfaces: one faces the pharynx, its mucous membrane is lined with prismatic ciliated epithelium; the other is directed towards the mouth, its mucous membrane is lined with squamous stratified epithelium. The free, concave, edge of the palatine curtain is called the palatine arch, which passes into the palatopharyngeal arches, which run along the lateral walls of the pharynx to the dorsal wall of the esophagus and form an unpaired esophageal-pharyngeal arch above the entrance to the esophagus.

The basis of the palatine curtain is a muscular elephant, consisting of several muscles. Muscles carry out the movement of the palatine curtain. As a result of the contraction of these muscles, the palate shortens after the act of swallowing, rises during the act of swallowing and tightens, helping the tongue to form and push the food bolus into the throat.

Rice. 1. Language:

L - horses; B - cattle; D- sheep; G - pigs; D - dogs; 1 - roller-shaped papillae; 2 - foliate papillae; 3 - fungiform papillae; 4 - tongue pillow; 5 - top of the tongue 6 - the body of the tongue; 7 - the root of the language.

Tonsils. Between the palatine curtain and the root of the tongue on the right and left are the palatine tonsils with lymphatic follicles. In horses, on the pharyngeal and oral surfaces of the palatine curtain, lymphatic follicles are laid in the mucous membrane, forming an unpaired palatine tonsil. The tonsils serve as the first protective devices in the fight against infection that enters the body through the mouth and nasal openings.

(Fig. 1) - a mobile muscular organ, the role of which is to capture food, putting it on the teeth when chewing, moving from the oral cavity to the pharyngeal cavity, determining its nature and quality. The language is divided into root, body and apex.

The root of the tongue extends from the larynx to the last molar, the body of the tongue lies between the molars, the tip of the tongue is the anterior free-lying part. The upper surface of the tongue is called its back. The mucous membrane of the bottom of the oral cavity passes to the lower surface of the tongue, forming a fold - the frenulum of the tongue. The mucous membrane of the upper and lateral surfaces of the tongue forms special protrusions - papillae: filiform, cone-shaped, roller-shaped, mushroom-shaped, leaf-shaped. Filiform and cone-shaped papillae cover the back and tip of the tongue and have a mechanical significance - they help the movement of food. Fungiform papillae are located mainly on the lateral surfaces of the body of the tongue and the upper surface of the tip of the tongue. The roller-shaped papillae are located on the back of the tongue; unlike fungiform papillae, they are immersed in the thickness of the mucous membrane. Foliate papillae in the form of several parallel folds separated by narrow grooves are visible, one on each side along the edges of the root of the tongue.

Serous glands open at the bottom of the grooves. The papillae of the tongue, with the exception of the filiform ones, contain taste buds and are the organ of taste. In the thickness of the mucous membranes of the root and lateral edges of the tongue, there are many lymphatic follicles and mucous glands that secrete a secret that moisturizes the tongue.

The muscles of the tongue have a longitudinal, transverse and vertical direction of the fibers. Contracting, they shorten, thicken, narrow the tongue. The muscles coming from the hyoid bone and chin pull the tongue back, push it forward, carry out lateral movements, push the food lump.

Teeth(Fig. 2). The function of the teeth is to mechanically process food. In each tooth, it is customary to distinguish between a crown - a part that freely protrudes into the oral cavity; the neck, covered by the gum, and the root, immersed in the alveolus of the corresponding bone: the upper, mandible or incisive bones.

Rice. 2. Cow Teeth:

BUT-incisor; B- longitudinal cut of the incisor tooth; B-structure of the molar; 1 -crown; 2 - root; h- neck; 4 - chewing surface; 5 - cement; 6 - enamel; 7 - dentin; 8 - tooth cavity filled with pulp; about- cups; 10 - gum; 11 - mandibular bone with dental alveolus; 12 - periosteum of the lunula.

Each tooth is made up of dentin, enamel, cementum and pulp. The main part is dentin. Inside the tooth, starting from the end of the root, there is a dental cavity filled with dental pulp, in which blood vessels and nerves branch.

There are short-crown and long-crown teeth. In short-crown teeth, the enamel covers the dentin only in the area of ​​the crown, in the form of a cap, and the cementum covers the root of the tooth. In long coronal teeth, not only the crown, but also the root of the tooth is covered with enamel, and the entire tooth over the enamel and even cups formed by folds of enamel on the rubbing surface of the tooth are covered with cement. The crown of the tooth is very long and protrudes from the dental alveolus as it is worn away. Short-crowned teeth include all milk teeth, permanent incisors of cattle, all teeth of pigs and dogs; to long-crown - all permanent teeth of a horse and permanent molars of cattle.

The teeth are arranged in the form of dental arcades and are divided into incisors, canines and molars. Domestic animals have six incisors on the lower jaws and incisors. The exception is ruminants, which have eight incisors on the lower jaws, and no teeth on the incisal bones.

The incisors have the following names (counting from the middle): hooks, middle and edges; in ruminants on the lower jaws there are medial medial (near the toes) and median lateral (next to the margins). The incisors grab the food and bite it off.

The fangs are located one on each side in the upper and lower arcades. Ruminant tusks do not. Fangs serve as a weapon of defense and attack.

Horses and ruminants have six molars on each jaw, seven in pigs, and seven in dogs (on the lower jaws). Molar teeth grind food. Three or four front molars on each side have milk predecessors - premolars. The posterior molars, molars, do not have milk predecessors.

At ruminants 20 primary teeth (8 mandibular incisors and 12 premolars) and 32 permanent teeth (8 incisors, 12 premolars and 12 molars). The molars of ruminants are of the lunate type.

At pigs 28 primary teeth (12 incisors, 4 canines and 12 premolars) and 44 permanent teeth (12 incisors, 4 canines, 16 premolars and 12 molars). The permanent molars of pigs are tuberculate.

At dogs 32 milk (12 incisors, 4 canines and 16 molars) and 42 permanent teeth (12 incisors, 4 canines, 26 molars, of which 16 premolars and 10 molars). The permanent teeth of dogs are three-toothed and multi-cusp.

At horses 24 milk teeth (12 incisors and 12 premolars) and 40 permanent teeth in males (12 incisors, 4 canines, 12 premolars and 12 molars). In mares, fangs are rudimentary and are more often absent. Incisor teeth in the form of a curved wedge with a convex, labial, and concave, lingual, surface.

The structure of the teeth is in accordance with the nature of chewing animals. In herbivores, it is carried out by grinding movements of the lower jaw down and up, but also to the sides and forward. The chewing surfaces of the molars are located at the same time, like millstones, one above the other and grind everything that is between them. Ruminants grind food especially carefully when they regurgitate their cud.

In pigs and dogs, the lower jaw can only be lowered and raised, which achieves cutting and crushing of the feed masses.

Determining the age of pets by teeth is based on the time of appearance of milk teeth and their replacement by permanent ones, and in horses, in addition, on the erasure and change in the shape of the rubbing surface of the incisor teeth.

Rice. 3. Wall and wall salivary glands:

BUT- cattle; B- pigs; AT- horses; 1 - parotid salivary gland; 2 - submandibular salivary gland; h- buccal glands; 4 - labial glands; 5 - duct of the submandibular salivary gland; 6 - sublingual short duct salivary gland; 7 - sublingual salivary gland is a ductal gland.

The replacement of milk incisors with permanent ones begins in foals from 2.5 years and ends by 5 years. Dairy incisors are easy to distinguish from permanent ones: they are whiter, smaller, with a clearly defined neck and a shallow (up to 4 mm) cup. In young animals, the upper and lower incisor teeth are located towards each other in the form of an arc. The angle at which the incisor teeth converge becomes sharper with age.

The cross-sectional shape of the rubbing surface of the permanent incisors changes with age in the following order: in foals it is transversely oval, in middle-aged horses it is round; in old animals it is triangular, in very old animals it is obovate. During this period, the dental calyx disappears, the calyx mark and the dental star appear.

Salivary glands(Fig. 3). In the wall of the mucous membrane of the lips, cheeks, tongue, palatine curtains, parietal salivary glands are laid in the form of separate formations or groups. Outside the oral cavity there are large parotid salivary glands: paired parotid, sublingual and submandibular. The secret of the salivary glands, pouring into the oral cavity through the excretory ducts, is called saliva.

In functional terms, the salivary glands are divided into serous, mucous and mixed. There is a lot of protein in the secretion of the serous glands, so they are also called proteinaceous. The secret of the mucous glands contains the mucous substance mucin. Mixed glands secrete a protein-mucous secret.

The parotid salivary gland is serous (in carnivores it is mixed in some areas), alveolar in structure. In cattle, pigs and dogs it is triangular, in horses it is rectangular. Lies near the base auricle. Its excretory duct opens on the eve of the oral cavity: in horses and dogs at the level of the 3rd, in cattle the 3rd-4th, in pigs the 4th-5th upper molar.

The submandibular salivary gland is mixed. In cattle, relatively long, extending from the atlas to the submandibular space, the excretory duct opens in the sublingual wart at the bottom of the oral cavity. In pigs and dogs, it is round, covered by the parotid gland; the excretory duct opens in pigs near the frenum of the tongue, in dogs - in the hyoid wart.

The sublingual salivary gland is double. In cattle, the short duct part lies under the mucous membrane of the floor of the oral cavity, numerous short excretory ducts open on the side of the body of the tongue; the long ductal part is located next to the previous one, its long excretory duct opens in the sublingual wart. Functionally, the long-duct part is mixed, the short-duct part is mucous. Horses have only a short ductal part, the secret is mixed in nature.

The mouth, the oral cavity is topographically divided into the so-called vestibule of the mouth and the oral cavity itself (Fig.). The term "mouth" also refers to the mouth opening enclosed by the lips of the mouth. The boundaries of the vestibule of the mouth are in front of the lips and cheeks, and behind the alveolar processes of the jaws and teeth. The oral cavity is bounded from above by the arch of the hard palate; the basis of the bottom of the oral cavity is the maxillo-hyoid muscle with the genio-lingual, genio-hyoid, hyoid-lingual muscles located above it. The posterior border of the oral cavity is represented by a soft palate, with the contraction of the muscles of which a pharyngeal opening is formed, also limited by the root of the tongue and the anterior palatopharyngeal arches. When swallowing, the soft palate separates the oral cavity and the oral part of the pharynx from the nasal.

Rice. 1-3. Oral cavity. Rice. 1. Sagittal section. Rice. 2. Front view (the corners of the mouth are cut). Rice. 3. frontal section:

1 - palatum durum ( solid);
2 - dentes (teeth);
3 - labium sup. (upper lip);
4 - rima oris;
5 - labium inf. (underlip);
6 - vestibulum oris (vestibule of the mouth);
7 - mandible;
8 - m. mylohyoideus;
9 - m. genlohyoideus;
10-gl. sublingualis;
11 - m. genloglossus;
12 - os hyoideum;
13 - isthmus faucium (pharynx);
14 - lingua (language);
15 - palatum molle (soft palate);
16 - cavum oris proprium;
17 - frenulum labii sup.;
18 - gingival (gingiva);
19 - arcus palatoglossus (palato-lingual arch);
20 - tonsilla palatine (palatine tonsil);
21 - uvula (tongue);
22 - frenulum labii inf.;
23 - arcus palatopharyngeus (palatopharyngeal arch);
24 - plicae palatinae transversae;
25 - venter ant. m. digastrici;
26-m. buccinator;
27 - corpus adiposum buccae.

The oral cavity is lined with a mucous membrane, in the thickness of which there is a large number of small ones. The mucous membrane of the oral cavity is covered with stratified squamous epithelium, which is located on a connective tissue basis. This layer without a sharp border passes into the submucosal layer. There is no submucosal layer in the gum, tongue, lateral parts of the hard palate and the region of the palatine suture. Blood supply, lymph drainage and innervation of the walls of the oral cavity are closely related to the vascular and nervous systems jaws (see). The ducts of the salivary glands open into the oral cavity.

It should be pointed out changes in the structure of the oral mucosa with age: thinning occurs, signs of its degeneration appear, the integrity of the basement membrane is disturbed, it becomes denser. Elongation of the venous part of the capillaries, a decrease in their number, and a slowdown in blood flow were noted. In the cells of the integumentary epithelium, the tendency to keratinization increases with age. All these changes have a significant impact on the occurrence and development of the pathological process, and they must be taken into account when examining or treating a patient.

Oral cavity - initial department digestive tract. Here, food undergoes mechanical and partially chemical processing (see Chewing). In the mucous membrane there is a row, due to which taste, tactile and pain sensitivity. Pain and temperature sensitivity of the oral mucosa is reduced in comparison with the skin and is not the same in different areas.

The mouth contains a diverse microbial flora: in addition to permanent, adapted microbes, here long time microorganisms brought from outside may be present. In this regard, a distinction is made between permanent and random microflora of the oral cavity, and the permanent microflora serves as a biological barrier for microbes entering the oral cavity from the outside.

With a decrease in the body's resistance, the pathogenic properties of some microbes, usually vegetating in the oral cavity, may appear. Prolonged use of antibiotics can also disrupt the biological barrier and promote 'medicated' mucosal lesions. The causative agents of diseases of the mucous membrane are most often Candida fungi, and gram-negative bacteria. Fungal lesions of the mucous membrane are not uncommon in aspergillosis, etc., as well as in actinomycosis, blastomycosis.

Among diseases of the mucous membrane, gingivitis (see) and (see) are most often observed. Stomatitis can occur with beriberi, blood diseases, after taking some medicines(bismuth,

The oral cavity is the beginning of the digestive apparatus. It has the same complex structure as other systems and organs of the human body.

The structure of the oral cavity

From an anatomical point of view, the oral cavity is a combination of the following parts:

1. The vestibule of the mouth, that is, the space between the cheeks and lips on one side and the teeth and gums on the other.
2. Directly the oral cavity, bounded from above by the palate, from below - by the bottom, on the sides and in front - by the gums and teeth.

Lips can be called a kind of "entrance" to the mouth. These are skin-muscle folds, in which several parts are distinguished:

• skin - located on the outer (visible) side. Covered with a layer of keratinized epithelium. It contains glands that produce sweat and sebum. Hairs also grow on the outer surface of the lips;
• intermediate - a pink area covered with skin. Cornification is observed only on the outside. Where the skin passes into the mucous membrane, a red border is clearly visible. This area contains a huge number of blood vessels and nerve endings, which ensures its increased sensitivity;
• mucous - localized with inside lips. This part is covered with squamous epithelium, not prone to keratinization.

The buccal region is located on both sides of the human face. The cheeks consist of the buccal muscle, are covered with skin and contain a fatty body.

In the oral cavity there are some organs that are important for maintaining normal human life:

1. Tongue - an unpaired outgrowth of a spade-shaped pinkish color, almost completely filling the oral cavity. The tongue is formed by striated muscle tissue. From above, it is covered with a mucous membrane, on which leaf-shaped, trough-shaped and mushroom-shaped papillae are located, containing taste buds in their walls. The tongue is involved in the chewing process, taste perception and salivation, provides a person's ability to articulate speech. There are the following main parts:

• root (about 1/3 of the tongue near the pharynx, at its base are the tonsils);
• body (about 2/3 of the tongue closer to the teeth);
• tip (adjacent to the back surface of the incisors);
• back (upper surface);
• frenulum (a fold of mucous that connects the bottom of the tongue with the bottom of the mouth).

2. Gums - mucous covering the alveolar process of the upper and alveolar parts of the lower jaw. There is such a division of the gums:

• free, or marginal gums - a smooth area of ​​\u200b\u200bmucosa that encircles the neck of the tooth;
• gingival sulcus - a recess between the gum and the tooth;
• interdental papilla - the gum area between adjacent teeth;
• attached, or alveolar gum - a fixed part, fused with the periosteum of the alveolar bone and cementum of the dental root.

3. Teeth - organs that directly perform the function of chewing food. In an adult, there are normally 28-32 teeth in the mouth (third molars may be absent). Anatomically, a tooth consists of a root, neck and crown, which is covered with enamel. Under the enamel is a strong tissue of light yellow color, which is the "backbone" of the tooth - dentin. Inside there is a pulp chamber filled with pulp - connective tissue that provides nutrition to the tooth. Depending on their functions, several types of teeth are distinguished:

• incisors - provide biting food;
• fangs, or eye teeth - contribute to tearing food into small pieces;
• premolars and molars - grind food, grinding it.

4. The palate is the upper part of the oral cavity covered with a mucous membrane, which is one of the components of the articulatory apparatus. There are two types of palate:

• hard - is a bone wall separating the oral and nasal cavities. It is slightly curved and resembles a vault convex upwards;
• soft is a fold of mucous that hangs over the root of the tongue and separates the oral cavity from the pharynx. The uvula is located on the soft palate, which plays an important role in the formation of sounds.

Also, paired ducts of the salivary glands enter the oral cavity:

• the sublingual is the smallest of the major glands. Has an oval shape. The gland is localized at the bottom of the oral cavity on the sides of the tongue. The saliva produced is rich in mucin, serous secretion and is characterized by high alkaline activity;
• submandibular - differs in a rounded shape, comparable in size to a walnut. The gland is located in the submandibular triangle. It secretes saliva of less acidity than the parotid gland, but containing a mucous and serous secretion;
• parotid - the largest among the other glands. It has a grayish-pink tint and irregular shape. A pair of these glands is located under the skin on the lateral surface of the lower jaw downwards from the ears. The secreted saliva is characterized by high acidity and is saturated with sodium chloride and potassium chloride.

The process of processing food begins in the mouth. Crushed and saliva-moistened food is collected in a lump, which is then affected by the enzymes that make up saliva.

Functions of the oral mucosa

The mucous membrane covers almost the entire oral cavity. It is characterized by high rates of regeneration, as well as resistance to various irritants. The mucous membrane performs a number of important functions:

1. Protective - the mucosa retains various microorganisms on its surface, preventing them from penetrating into the body.
2. Receptor, or sensitive - the presence of a huge number of receptors on the mucous membrane turns it into an excellent indicator that instantly responds to possible negative effects.
3. Suction - some protein and mineral compounds, for example, contained in medicines, are absorbed through the mucosa.

The structure of the oral mucosa

Stratified squamous epithelium

It lines the entire surface of the mucosa. In children, this layer is thin, but with age it becomes thicker and slightly coarsens. With the approach of old age, the reverse process starts, and the epithelium becomes thinner.

On the lips, cheeks, soft palate, below the tongue and at the bottom of the oral cavity, the epithelium does not become keratinized, it is relatively thin and has a pinkish color. In areas that are exposed to aggressive effects, the epithelium is prone to keratinization (as a rule, this is characteristic of the hard palate, gums and root of the tongue). It is believed that the degree of keratinization depends on the amount of glycogen: where the epithelium remains soft, a lot of glycogen is found, and vice versa.

Among the functions of the epithelial layer:

• barrier - prevents injury to the mucosa;
• protective - along with the periodically exfoliating surface layer of the epithelium, pathogens are removed from the mouth.

lamina propria mucosa

This dense layer of connective tissue lies directly below the epithelial layer. The lamina propria penetrates the epithelial layer with the help of papillae containing blood vessels and nerves. Thanks to this “bond”, a more efficient exchange of substances between the layers is ensured, as well as their strong connection. Among other things, on the own plate of the mucosa are lymphatic vessels, salivary and sebaceous glands.

Submucosa

A layer consisting of relatively loose connective tissue. There is no clearly defined line between the submucosal and the proper mucosal layer. The submucosa is characterized by the presence of a deep network of vessels and small salivary glands. The more pronounced this layer, the more mobile the entire mucous membrane.

The structure of the oral cavity allows it to endure regular potentially traumatic effects without much loss: too hot or cold dishes, smoking, careless treatment at the dentist, or accidental biting of the cheek. But do not abuse such "patience": even he can come to an end.

The oral cavity is the beginning of the digestive tract; area where the primary processing food. Structural features allow this department to perform other important functions.

The human oral cavity.

Anatomically, the site consists of two sections - the vestibule and the actual oral cavity. The vestibule is an area bounded by the lips, the front of the teeth, and the cheeks. The human oral cavity itself is limited to the palate, the inner side of the teeth, gums, bottom.

Lips

Lips - folds formed by muscles and skin, having a characteristic structure:

• keratinized epithelium from the outside;
• mucous membrane inside;
• intermediate area.

The lips are connected to the gums by elastic folds - bridles. Small ones are located under the mucosa. Lips capture food, participate in the pronunciation of sounds, facial expressions.

Cheeks

The structure of the oral cavity.

The outer side of the cheeks is covered with skin epithelium, the inner side is lined with mucous membranes. Between them are elastic muscle fibers. Located under covers adipose tissue. In children, it is more pronounced due to Bish's lumps, which become flat with age. Under the mucosa are small salivary glands, and near the molars - large parotid.

Gums

The human gum is a mucous membrane that covers the alveolar areas of the jaws. The gum includes several parts:

• free edge encircling the neck of the tooth;
• papilla located between chewing units;
• a groove located between the tooth and the gum;
• attached part connected to the periosteum.

Teeth

Each tooth is made up of a layer of enamel, dentin, and a soft pulp through which blood vessels and nerve endings pass. Allocate a dental crown (visible part), root, neck. Teeth are divided into groups:

Language

The tongue is the most mobile muscle in the human body. Thanks to this feature, he takes part in pronouncing the most complex sounds. The tip of the tongue is near the teeth, the root with the tonsils is near the pharynx itself, and the upper surface of the organ is called the back.

The tongue occupies most of the space of the oral cavity. The surface of the organ is covered with papillae of various shapes, which play the role of taste buds.

Sky

From above, the oral cavity is bounded by the palate. There are two types of it:

mucous membrane

The entire human oral cavity is covered with a mucous membrane characterized by a high degree of regeneration. It is formed by squamous epithelium. On the hard palate and the root of the tongue it is keratinized, on the cheeks, gums, soft palate it is soft. In the epithelium are small salivary glands. In addition to them, there are large glands:

• parotid (on the side of the lower jaw);
• sublingual (under the tongue);
• submandibular (in the submandibular triangle).

The function of the salivary glands is the secretion of saliva, necessary for the processing of incoming food.

Main functions

The structure of the oral cavity determines the functions that it performs:

1. 1. Participation in the digestive process. The oral cavity is the area where the breakdown of carbohydrates, grinding, cooling of food, and the formation of a food lump occur.
   2. Articulation, the formation of human speech.
   3. Immune protection with the help of the tonsils, which serve as a "gateway" for infection to enter Airways. Saliva contains substances that inhibit the activity of harmful microorganisms, preventing them from entering the digestive tract.
   4. Breath. Under normal conditions, breathing occurs through the nose, but sometimes the mouth plays the role of a conductor of oxygen.

The functions of the oral cavity are important for maintaining the overall health of the body and for the quality of life. It is important to monitor her hygiene, timely eliminate any diseases in this area.

Sources:

1. Kurepina M.M., Ozhigova A.P., Nikitina A.A. Human anatomy. Moscow, 2010.
2. Kosourov A.K., Drozdova M.M., Khairullina T.P. Functional anatomy of the oral cavity and its organs. St. Petersburg, 2006.

The actual oral cavity , cavum oris proprium, is bounded from above by a hard and partially soft palate, from below by the tongue and muscles that make up the bottom of the oral cavity, in front by the dentition and gums. The back wall of the oral cavity itself is formed by the soft palate, which, when contracted, can limit the opening - the pharynx, through which the oral cavity communicates with the pharynx.

With closed teeth, the oral cavity itself has the form of a gap, with the mouth open, it has an irregular ovoid shape. There are pronounced individual and age differences in the shape of the oral cavity itself. Brachycephalic mouths are wider, taller, and shorter than dolichocephalic ones, which are narrow, low, and long.

In newborns and children up to 3 months, the oral cavity is very small, it is short and low due to the weak development of the lower alveolar processes and the body of the lower jaw. With the development of the alveolar processes and the appearance of teeth, the oral cavity increases and acquires the shape of an adult cavity by the age of 17-18.

Solid sky. The hard palate, palatum durum, consists of the bony palate, palatum osseum (the palatine process of the upper jaw and the horizontal plate of the palatine bone, see the Bones of the Facial Skull section of this edition) and the soft tissues that cover it, and is a septum separating the oral cavity from nasal cavity (Fig. 81). Accordingly, the hard palate has two surfaces: the oral, facing the oral cavity, and the nasal, which is the bottom of the nasal cavity.

Rice. 81. The sky after removal of the mucous membrane. 1 - hard palate; 2 - large palatine artery; 3 - the mouth of the duct of the parotid salivary gland; 4 - pterygoid hook; 5 - muscle straining the palatine curtain; 6 - mucous membrane of the oral cavity; 7 - muscle that raises the palatine curtain; 8 - upper constrictor of the pharynx; 9 - palatoglossal muscle; 10 - reed muscle; 11 - palatopharyngeal muscle; 12 - back of the tongue; 13 - lower dental arch; 14 - pharynx; 15 - palatine tonsil; 16 - pterygo-mandibular suture; 17 - buccal muscle; 18 - palatine glands; 19 - gum; 20 - upper dental arch

Depending on the height of the alveolar processes of the upper jaw, the degree of concavity of the hard palate itself (both in the transverse and sagittal directions), a vault, or dome, of the upper wall of the oral cavity of various heights is formed. In people with a dolichocephalic skull, a narrow and high face, the arch of the palate is high, in people with a brachycephalic skull and a wide face, the arch of the palate is flatter (Fig. 82). In newborns, the hard palate is usually flat. As the alveolar processes develop, the vault of the sky is formed. In old people, due to the loss of teeth and atrophy of the alveolar processes, the shape of the palate approaches flat again.

The bony surface of the hard palate is uneven, there are a number of holes, canals, furrows, and elevations in the bone. In the middle, at the junction of the palatine processes, a suture of the hard palate, raphe palati, is formed. In newborns, the palatine processes of the upper jaw are interconnected by a layer of connective tissue. Then, in children, the formation of bony protrusions from the side of the palatine processes occurs, growing towards each other. With age, the connective tissue layer decreases, and the bone layer increases. By the age of 35-45, the bone fusion of the palatine suture ends and the junction of the processes acquires a certain relief: concave, smooth or convex. With a convex form of the palatine suture in the middle of the sky, a protrusion of various sizes is noticeable - the palatine roller, torus palatinus. Sometimes this roller can be located to the right or left of the midline. The presence of a pronounced palatine ridge greatly complicates the prosthetics of the upper jaw. The palatine processes of the upper jaw, in turn, fuse with the horizontal plates of the palatine bones, forming a transverse bone suture. However, this seam is usually not noticeable on the surface of the hard palate. The posterior edge of the hard palate has the form of arcs, connected by medial ends and forming a protrusion - the posterior nasal spine, spina nasalis posterior.

Rice. 82. Differences in the shape of the sky (according to E. K. Semenov). a - high vault sky; b - flat vault of the sky; c - narrow and long sky; d - wide and short palate

The mucous membrane of the hard palate is covered with stratified squamous keratinized epithelium and is tightly connected to the periosteum almost throughout. In the region of the palatine suture and in the areas of the palate adjacent to the teeth, the submucosal layer is absent and the mucous membrane is directly fused with the periosteum. In areas outside of the palatine suture, there is a submucosal layer penetrated by bundles of fibrous connective tissue that connect the mucous membrane with the periosteum. As a result, the mucous membrane of the palate is motionless and fixed to the underlying bones. In the anterior sections of the hard palate in the submucosal layer between the connective tissue trabeculae there is adipose tissue, and in the posterior sections of the palate there are accumulations of mucous glands. Outside, at the point of transition of the mucous membrane from the hard palate to the alveolar processes, the submucosal layer is especially well expressed and large neurovascular bundles of the palate are located here (see Fig. 81).

The mucous membrane of the hard and soft palate differs in color. On the hard palate it is pale pink, while on the soft palate it is pinkish red. The mucous membrane of the hard palate forms a series of elevations. At the anterior end of the longitudinal palatine suture, near the central incisors, the incisive papilla, papilla incisiva, is clearly visible, which corresponds to the incisal foramen located in the bony palate, foramen incisiuum. The incisive canals, sapa-les incisivi, open into this opening, in which the naso-palatine nerves pass. This area is the site of administration of anesthetic solutions for the purpose of local anesthesia. anterior section sky.

In the anterior third of the hard palate, to the sides of the palatine suture, there are transverse folds of the mucous membrane, plicae palatinae transversae (from 2 to 6). The folds are usually curved and may be interrupted and divided. In children, the transverse folds are well expressed, in adults they are smoothed out, and in the elderly they may disappear. The number of folds, their length, height and tortuosity are different. More often there are 3-4 folds. These folds are rudiments of the palatine folds, which in carnivorous animals contribute to the mechanical processing of food. 1-1.5 cm medially from the gingival margin of the 3rd molar, on each side, there is a projection of the large palatine opening, and directly posterior to it - the small palatine opening of the large palatine canal, canalis palatinus major, through which the palatine blood vessels and nerves. In some cases, the projection of the large palatine opening may be in the 1st or 2nd molar, which is important to consider when performing anesthesia and surgical interventions.

At the posterior edge of the hard palate on the sides of the midline are palatine fossae, foveolae palatinae. Sometimes the hole is only on one side. These pits, being a border formation with a soft palate, are used by dentists to determine the boundaries of a removable denture.

The blood supply to the hard palate is carried out mainly by the large and small palatine arteries, which are branches of the descending palatine artery. The large palatine artery enters the palate through the large palatine opening and spreads anteriorly, giving branches to the tissues of the palate and gums. The anterior portion of the hard palate is supplied with blood by the incisive artery (a branch of the posterior artery of the nasal septum). Blood from the hard palate flows through the veins of the same name: the greater palatine - into the pterygoid venous plexus, the incisive vein - into the veins of the nasal cavity.

The outflow of lymph from the tissues of the hard palate is carried out through the efferent lymphatic vessels passing under the mucous membrane of the palatine arches in The lymph nodes lateral wall of the pharynx and into the deep upper cervical nodes.

The innervation of the hard palate occurs due to the large palatine and ioso-palatine nerves (from the second branch of the trigeminal nerve).

Soft sky. The soft palate, palatum molle, forms mainly the posterior wall of the oral cavity. Only a small area of ​​the anterior soft palate belongs to top wall. The large, posterior, part of the soft palate hangs freely down and backwards, being called the palatine curtain, velum palatinum. However, the position and shape of the soft palate change depending on its functional state. So, in a relaxed state, for example, with calm breathing, the soft palate hangs vertically down. In this case, there is an almost complete separation of the oral cavity from the oral part of the pharynx and nasal cavity. At the moment of the act of swallowing, the soft palate, rising, is set horizontally, while isolating the oral cavity and the oral part of the pharynx from the nasal cavity. In people with a brachycephalic skull, the soft palate is flattened and lies almost horizontally. In individuals with a dolichocephalic skull shape, the soft palate descends more vertically. The soft palate in newborns is formed from two halves that grow together after birth. The tongue may be split. In newborns and children infancy the soft palate lies horizontally due to the insignificant height of the oral cavity.

The sizes of the soft palate are individually different and vary in length from 30 to 75 mm, averaging 35-50 mm, and in width - 25-60 mm. In newborns, the soft palate reaches a length of 25-40 mm, and a width of 30-50 mm. The length of the tongue at this age is on average 7 mm.

The soft palate consists of a fibrous plate - the palatine aponeurosis with the muscles of the soft palate attached to it and the mucous membrane covering it from above and below. The fibrous plate in front is attached to the hard palate. The mucous membrane lining the soft palate from the side of the oral cavity is covered with stratified squamous non-keratinized epithelium, and from the side of the nasal cavity - multi-row ciliated epithelium. Both surfaces of the tongue in adults are covered with stratified squamous epithelium, but in newborns, ciliated epithelium is still preserved on its back surface, which is later replaced by a flat one. On the border of its own and submucosal layers in the soft palate there is a highly developed layer of elastic fibers. Numerous mucous glands lie in the submucosal layer. In some places, the bodies of the mucous glands lie between the bundles of muscles of the soft palate. The excretory ducts of the glands open on the oral surface of the palate.

The posterior edge of the soft palate in the middle has a protrusion hanging down, called the tongue, uvula. Lateral to the uvula, the posterior edge of the soft palate forms on each side a pair of palatine arches, which are folds of the mucous membrane with muscles embedded in them. The anterior palate-lingual arch, arcus palatoglossus, runs from the middle part of the palate to the lateral surface of the posterior part of the tongue. The posterior, palatopharyngeal arch, arcus potatopharyngeus, goes to the lateral wall of the pharynx. Between the palatoglossal and palatopharyngeal arches, a triangular depression is formed - the tonsil fossa, fossa tonsillaris. The lower part of the tonsil fossa is deeper and is called the tonsil sinus, sinus tonsillaris. It contains the palatine tonsil (see section The actual oral cavity, this edition). Above the tonsil there is a small depression - above the tonsil fossa, fossa supratonsillaris.

The soft palate contains the following muscles (Fig. 83).

1.Muscle that tenses the soft palate, m. tensor veli palatini, originates from the outer base of the skull in three bundles: anterior - from the scaphoid fossa of the pterygoid process and its inner plate, middle - from the outer surface of the cartilaginous and membranous parts of the auditory tube and from the lower surface of the large wing of the sphenoid bone medially from the spinous and oval holes , rear - from the angular spine of the large wing. Muscle fibers in the form of a flat muscle plate of a triangular shape descend down and forward to the hook of the pterygoid process and, not reaching 2-10 mm before it, pass into a tendon 2-6 mm wide, which, throwing over the hook, splits into two parts - the outer and internal. The outer part of the tendon, smaller, passes into the buccal-pharyngeal fascia, partially attaching to the posterior surface of the alveolar process. The inner part of the tendon, thicker, fan-shaped expands and passes into the palatine aponeurosis. With the contraction of the right and left muscles, stretching (tension) of the soft palate occurs. Between the surface of the hook of the pterygoid process and the tendon of the muscle is a small synovial bag, bursa synovialis m. tensoris veil palatini.

The muscle that strains the soft palate, in the area from the base of the skull to the hook of the pterygoid process, lies between the inner plate of the pterygoid process and the medial surface of the internal pterygoid muscle. In this case, both muscles usually (in 74% of cases) fit snugly against each other. Less often (in 26%) there is a layer of fiber between them.

Rice. 83. Muscles of the soft palate. 1 - muscle straining the palatine curtain; 2 - muscle that raises the palatine curtain; 3 - pterygoid hook; 4 - palatoglossal muscle; 5 - reed muscle; 6 - palatopharyngeal muscle

Function: stretches the soft palate and palatine aponeurosis and at the same time expands the lumen of the auditory tube.

2.The muscle that raises the soft palate, m. levator veli palatini, starts in two bundles from the lower surface of the stony part temporal bone anterior to the internal canal carotid artery and from the posterior third of the cartilaginous section of the auditory tube. The beginning of a muscle can be both muscular and tendon. Both initial muscle bundles form a muscular belly of a cylindrical or slightly flattened shape, located medially m. tensor veli palatini. The muscular abdomen is usually surrounded by fiber, and therefore purulent processes that begin near the pyramid of the temporal bone can descend through the fiber to the back of the sky. Sometimes a muscle throughout can have two parts separated by fiber. The length of the muscle that lifts the soft palate is related to its size. In people with a short soft palate, this muscle is long, and with a long soft palate, it is shorter. The muscle that lifts the soft palate enters it in the transverse direction between the layers of the palatopharyngeal muscle and is divided into three bundles: anterior, middle and posterior. The anterior bundle intertwines with the fibers of the palatopharyngeal muscle and passes into the palatine aponeurosis. Medium beam, the most developed, connects with the fibers of the same muscle of the other side and forms the posterior edge of the soft palate. The posterior bundle, together with the fibers of the palatopharyngeal muscle, goes to the uvula.

Function: raises the soft palate and participates, together with other muscles of the palate, in separating the nasal cavity from the oral part of the pharynx, and also narrows the pharyngeal opening of the auditory tube.

3.Palato-pharyngeal muscle, m. palatopharyngeus, starting in the submucosal layer of the posterior pharyngeal wall and from the inner surface and posterior edge of the thyroid cartilage, goes up in the thickness of the palatopharyngeal fold. The length of the palatopharyngeal muscle depends on the shape of the skull. In brachycephals, it is longer (35-40 mm) than in dolichocephals (20-35 mm). The muscle has a triangular shape, expanding as it approaches the soft palate. The width of its initial part is 2-14 mm, and near the sky - 10-22 mm. The wider the soft palate, the wider the palatopharyngeal muscle. At the posterior edge of the levator palate muscle, the palatopharyngeal muscle is divided into two layers: anterior and posterior. The fibers of the anterior muscle layer are located in front (or below with a raised palate) from m. levator veli palatini, and the rear - behind (or above) this muscle. The front layer forms 2 bundles: outer and inner. The first is weakly expressed and passes into the buccal-pharyngeal fascia, the second, the main one, goes along the oral surface of the soft palate and connects with the fibers of the muscle of the same name on the other side, as well as with the fibers m. levator veli palatini. Part of the fibers of this bundle passes into the palatine aponeurosis. The posterior layer of the palatopharyngeal muscle is divided depending on the width of the soft palate into 3-5 bundles: with a narrow palate there are 3-4 bundles, with a wide palate - 5 bundles of muscle fibers. The bundles of the posterior muscle layer go both to the soft palate and to neighboring organs. Thus, the first muscle bundle is attached to the lower-posterior surface of the cartilaginous auditory tube, the second - to the posterior surface of the hook of the pterygoid process, the third - passes into the back of m. levator veli palatini, the fourth (rare) - goes to the posterior nasal spine, the fifth - goes to the uvula muscle.

Function: diverse due to the complexity of the muscle structure. It raises the pharynx, tongue, larynx, narrows the palatopharyngeal space, brings together the palatine arches, pulls the soft palate down and back until it touches the back wall of the pharynx, and expands the lumen of the auditory tube.

4.Palatolingual muscle, m. palatoglossus, arises from the transverse muscle of the tongue and goes up in the thickness of the anterior palatoglossal arch. In the upper part of the arch, the muscle thickens and expands up to 9 mm and, at the posterior-lower surface of the soft palate, is divided into two bundles: the anterior one, which enters the sky at the anterior edge of m. levator veli palatini, and posterior, entering the sky at the posterior edge of this muscle. The length of the muscle varies from 23 to 33 mm; most often it reaches 27-29 mm.

Function: narrows the pharynx and lowers the soft palate.

5.Lingular muscle, m. uvulae, unpaired, starts from the posterior nasal spine and partly from the mucous membrane of the bottom of the nasal cavity, lies at first under it and goes backwards and downwards, reaching the posterior edge of the soft palate, and enters the uvula. The shape of the muscle is oval, the length depending on the length of the soft palate is 23-37 mm, the width is 1.5-4.5 mm.

Function: raises and shortens the tongue.

Zev. Zev, isthmus faucium, is an opening that connects the oral cavity with the pharyngeal cavity. It is bounded from above by the posterior edge of the soft palate and the uvula, on the sides by the palatine folds, and from below by the upper surface of the root of the tongue. The size and shape of the pharynx depend on the degree of contraction of the muscles of the soft palate and tongue. In cases of a significant increase in the size of the palatine tonsils (which happens in people suffering from frequent tonsillitis), the side walls of the pharynx are formed by the inner surfaces of the tonsils, while the pharynx narrows. In the region of the pharynx, there is a lymphoid ring, consisting of the pharyngeal, lingual, and tubal tonsils (see the Throat section of this publication).

The blood supply to the soft palate is made by small and large palatine arteries and thin branches from the arteries of the nasal cavity. The venous outflow goes through the veins of the same name to the pterygoid venous plexus and the veins of the pharynx.

Lymphatic vessels The soft palate carries lymph to the peripharyngeal, pharyngeal, and upper deep cervical lymph nodes.

The innervation of the soft palate occurs with small palatine nerves due to the pharyngeal plexus, a m. tensor veli palatini - from the mandibular nerve.

Rice. 84. Differences in the structure of the muscles of the floor of the mouth (according to V. G. Smirnov). a, b - the muscles of the floor of the oral cavity in dolichocephals are narrow and long, top and bottom view; c, d - the muscles of the floor of the mouth in brachycephals are wide and short, top and bottom view. 1 - maxillofacial muscle (top view); 2 - chin-hyoid muscle; 3 - tendon suture of the maxillofacial muscle; 4 - maxillofacial muscle (bottom view); 5 - anterior belly of the digastric muscle; 6 - hyoid bone

Floor of the mouth . The bottom of the oral cavity, or its lower wall, is formed by a combination of soft tissues located between the tongue and the hyoid bone. The basis of the bottom of the oral cavity is the diaphragm of the mouth, diaphragma oris, which consists of a paired maxillo-hyoid muscle. Above it lies on the sides of the midline the geniohyoid muscle, as well as the muscles of the tongue, starting on the hyoid bone (see the section Muscles of the hyoid bone, this edition). Together, they form the muscular basis of the floor of the mouth (Fig. 84).

1.Maxillofacial muscle, m. mylohyoideus, steam room, flat, trapezoidal, begins on the inner surface of the lower jaw along the linea mylohyoidea. The maxillo-hyoid line, as a rule, passes along the jaw on the right and left asymmetrically, as a result of which the level of the beginning of the right and left muscles may not be the same. In addition, the position of this muscle in relation to the upper edge of the alveolar process is different in different areas. So, at the level of the canine and the 1st premolar, the beginning of the maxillohyoid muscle is located at a distance of 18-29 mm from the upper edge of the alveolar process and 6-18 mm from the plane of the jaw base, and at the level of the 2nd-3rd molars - at 7-18 mm from the edge of the process and 16-22 mm from the base of the jaw. In relation to the tops of the molars, the beginning of the muscle falls below the first 5 teeth and above the 6-8th teeth. Muscle fibers are directed from top to bottom, from outside to inside and from front to back to the midline, where they form a tendon suture, raphe tendinei, running from the inner surface of the chin to the body of the hyoid bone. The fibers of the back of the muscle, starting between the 1st-3rd molars, are attached to the body of the hyoid bone.

The length of the muscle along the suture line ranges from 38 to 57 mm, and the width - from 30 to 50 mm. With a narrow and long jaw arch, the length of the muscle is large, and the width is smaller, with a wide and short one, vice versa. The thickness of the muscle increases posteriorly and reaches 4-6 mm in adults.

Small gaps can occur between the muscle bundles, through which purulent accumulations can spread from the oral cavity, as well as retention cysts of the sublingual salivary glands. Most often, such gaps are located in the center of the muscle at the level of the 2nd molar, retreating 20-30 mm medially from the jaw, and in the anterior areas of the muscle at the level of the canines near the jaw. In addition, there is a gap between the posterior edge of the maxillofacial and hyoid-lingual muscles.

2.Geniohyoid muscle, m. geniohyoideus, steam room, has the shape of a triangle, the top of which is directed towards the lower jaw, and the base - towards the hyoid bone. Muscle fibers begin with a short round tendon from the internal mental spine and go down and backwards, attaching to the body of the hyoid bone. The length of the muscle is 35-60 mm, the width at the point of attachment is 10-25 mm. The thickness of the muscle is 3-10 mm, most often 5-7 mm. With a narrow and long jaw, the muscle is long and narrow, with a wide and short jaw, it is short and wide.

Function: both muscles raise the hyoid bone, and with a fixed os hyoideum, lower the jaw.

The mucous membrane lining the bottom of the mouth passes here from the tongue. Thus, the bottom of the oral cavity is covered with a mucous membrane in front, partly on the sides of the tongue, between it and the gums of the lower jaw. In places of transition of the mucous membrane, a number of folds are formed.

1.Frenulum of the tongue, frenulum linguae, is a vertical fold of the mucous membrane that runs from the lower surface of the tongue to the bottom of the mouth. Anteriorly, this fold reaches the oral surface of the gingiva.

2.Hyoid folds, plicae sublinguals, lie on the sides of the frenulum of the tongue along the elevations (rollers) formed by the sublingual salivary glands. Small ducts of these glands open here. At the medial ends of the ridges, tubercles are formed - sublingual salivary papillae, carunculae sublinguales, on which the ducts of the unimandibular and large ducts of the sublingual salivary glands open. Anterior to the salivary papillae near the lower jaw are the ducts of the small incisive salivary glands, glandulae incisivae, which lie behind the incisors under the mucous membrane.

A feature of the structure of the mucous membrane of the bottom of the oral cavity is the presence of a well-developed submucosal layer, consisting of loose connective and adipose tissues. The mucous membrane easily gathers into folds, since it is weakly connected with the underlying tissues. Under the mucous membrane of the bottom of the oral cavity, the underlying muscles and organs are a number of cellular spaces.

1. The lateral cellular spaces of the floor of the oral cavity are limited from above by the mucous membrane, passing here from the tongue to the gum, from below by the maxillohyoid muscle, from the inside by the tongue and from the outside by the lower jaw. In these spaces lie the sublingual salivary glands surrounded by fiber. Suppurative processes are often localized here.

2. The internal intermuscular gap is unpaired, located between the two chin-lingual muscles. Made of loose connective tissue.

3. External intermuscular spaces are paired, formed between the chin-lingual and hyoid-lingual muscles.

4. The lower intermuscular space is unpaired, lies between the jaw-hyoid muscle and the anterior bellies mm. digastrici.

5. The submandibular cellular spaces are paired, formed from the outside by the inner surface of the lower jaw below the linea mylohyoidea, and from the inside by splitting the own fascia or the 2nd fascia of the neck. One plate of fascia lines m. mylohyoideus, and the second goes superficial to the submandibular salivary gland and is attached to the edge of the lower jaw. This cellular space contains the submandibular salivary gland, lymph nodes, vessels and nerves. The suppurative processes that form in this space are more or less isolated. However, with the accumulation of pus, it can spread along the duct of the gland into the corresponding lateral cellular space of the floor of the mouth.

The blood supply to the floor of the mouth is carried out by the lingual, facial, and superior thyroid arteries. The outflow of blood occurs in the corresponding veins.

Lymphatic vessels from the tissues of the floor of the mouth follow to the deep cervical and chin nodes.

Innervation - due to the lingual, hyoid, maxillo-hyoid (branch n. alveolaris inferior) nerves, as well as branches facial nerve(hind belly m. digastricus, m. styloglossus).