Salivary glands, composition, properties and significance of saliva. Protein composition of mixed human saliva: mechanisms of psychophysiological regulation Saliva disinfects

In the oral cavity there are a lot of small salivary glands located in the mucous membrane of the lips, cheeks, tongue, palate, etc. (Fig. No. 241). By the nature of the secretion secreted, they are divided into protein, or serous (produce a secret rich in protein and not containing mucus - mucin), mucous (produce a secret rich in mucin) and mixed, or protein-mucous (produce a protein-mucous secret). In addition to the small glands, the ducts of three pairs of large salivary glands located outside the oral cavity open into the oral cavity: parotid, submandibular and sublingual.

parotid gland- the largest of the salivary glands. Its mass is 25 g. It is located in the retromaxillary fossa in front of and below the outer ear. Its excretory duct (stenon duct) opens in front of the mouth at the level of the second upper molar. Allocates a serous secret containing a lot of water, protein and salts.

submandibular gland is the second largest salivary gland. Its weight is 15 g. It is located in the submandibular fossa. The excretory duct of this gland opens in the oral cavity under the tongue. Produces a protein-mucous secret.

sublingual gland- small, weighing about 5 g. It is located under the tongue on the maxillofacial muscle and is covered by the oral mucosa. There are several excretory ducts (10-12). The largest of these, the large sublingual duct, opens together with the submandibular duct under the tongue. It secretes a protein-mucous secret.

Each salivary gland receives dual innervation from the parasympathetic and sympathetic divisions of the autonomic nervous system. Parasympathetic nerves go to the glands as part of the facial (VII pair) and glossopharyngeal (IX pair) nerves, sympathetic - from the plexus around the external carotid artery. Subcortical centers of parasympathetic innervation of the salivary glands are located in the medulla oblongata, sympathetic - in the lateral horns of II-VI thoracic segments of the spinal cord. When the parasympathetic nerves are stimulated, the salivary glands secrete a large amount of liquid saliva, while the sympathetic glands secrete a small amount of thick, viscous saliva.

Saliva is a mixture of secretions of large and small salivary glands of the oral mucosa. This is the first digestive juice. It is a transparent liquid, stretching in threads, slightly alkaline reaction

(pH - 7.2). The daily amount of saliva in an adult is from 0.5 to 2 liters.

Saliva contains 98.5-99% water and 1-1.5% organic and inorganic substances. Of the inorganic substances, saliva contains potassium, chlorine - 100 mg% each, sodium - 40 mg%, calcium - 12 mg%, etc.

Of the organic substances in saliva, there are:

1) mucin - a protein mucous substance that gives saliva viscosity, glues the food lump and makes it slippery, making it easier to swallow and pass the lump through the esophagus; a large amount of mucin in the oral cavity is secreted mainly by small salivary glands of the oral mucosa;

2) enzymes: amylase (ptyalin), maltose, lysozyme.

Food stays in the oral cavity for a short time: 15-20-30 s.

Functions of saliva:

1) digestive;

2) excretory (excretory) - excretes metabolic products, medicinal and other substances;

3) protective - laundering of irritating substances that have entered the oral cavity;

4) bactericidal (lysozyme);

5) hemostatic - due to the presence of thromboplastic substances in it.

Saliva I Saliva (saliva)

the secret of the salivary glands, secreted in. Normally, in an adult, up to 2 l saliva. S.'s secretion rate is uneven: it is minimal during sleep (less than 0.05 ml per minute), when awake outside the meal is about 0.5 ml per minute, with stimulation of salivation C. increases to 2.3 ml in a minute.

Mixed S. is a viscous (due to the presence of glycoproteins) liquid with a specific gravity from 1001 to 1017. Some S.'s turbidity is caused by the presence of cellular elements. Fluctuations in the pH of saliva depend on the hygienic state of the oral cavity, the nature of food, and the rate of secretion (at a low rate of secretion, the pH of saliva shifts to the acid side, and when salivation is stimulated, it shifts to the alkaline side).

Approximately 99.5% of saliva consists of water, in which organic and mineral substances are dissolved. The main organic substances of S. are synthesized in the salivary glands (some glycoproteins, mucins, class A) and outside them. Some proteins of C. are of serum origin (certain enzymes, albumins, β-lipoproteins, immunoglobulins of classes G and M, etc.). Most people in S. contain group-specific, corresponding to blood antigens. The ability to secrete as part of S. is inherited. Specific proteins were found in saliva - salivoprotein, which promotes the deposition of phosphorocalcium compounds on the teeth, and phosphoprotein, a calcium-binding protein with a high affinity for hydroxyapatite, which is involved in the formation of tartar and plaque.

The main enzymes of S. are (α-amylase), which converts polysaccharides to di- and monosaccharides, and α-glycosidase, or , which breaks down maltose and sucrose. In saliva, lipases, phosphatases, and others were also found. In mixed S., its esters, free esters, glycerophospholipids, (estrogen, testosterone), various and other substances are also present in small quantities.

The mineral substances that make up S. are represented by anions of chlorides, bromides, fluorides, iodides, phosphates, bicarbonates, sodium cations, potassium, calcium, magnesium, copper, strontium, etc.

By wetting and softening solid food, S. ensures the formation of a food bolus and facilitates the swallowing of food. After impregnation, S. already in the oral cavity undergoes an initial chemical treatment, during which they are partially hydrolyzed by α-amylase to dextrins and maltose. The dissolution of the chemicals that make up food in saliva contributes to the perception of taste by the taste analyzer. S. has a protective function, clearing the mucous membrane of the oral cavity from bacteria and their metabolic products, food debris, and detritus. The immunoglobulins and lysozyme contained in C. also play a protective role. As a result of the secretory activity of the large and small salivary glands, the mouth is moistened, which is a necessary condition for the implementation of bilateral transport of chemicals between the oral mucosa and saliva.

The amount, chemical composition, and properties of S. vary depending on the nature of the causative agent of secretion (for example, the type of food taken), and the rate of secretion. So, when eating biscuits, sweets in mixed S., the level of glucose and lactate temporarily increases; when salivation is stimulated in S., sodium and bicarbonates sharply increase, the level of potassium and iodine does not change or slightly decreases, in S. there are several times more thiocyanates in smokers than in non-smokers. The chemical composition of S. is subject to daily fluctuations, it also depends on age (in the elderly, for example, the amount of calcium increases significantly, which is important for the formation of dental and salivary calculus). Changes in S.'s structure can be connected with reception of medicinal substances and intoxications. The composition of S. also changes in a number of pathological conditions and diseases. So, with dehydration of the body, a sharp decrease in salivation occurs; with diabetes in saliva, the amount of glucose increases; at uremia in S. the content of residual nitrogen considerably increases.

1. Small medical encyclopedia. - M.: Medical Encyclopedia. 1991-96 2. First aid. - M.: Great Russian Encyclopedia. 1994 3. Encyclopedic dictionary of medical terms. - M.: Soviet Encyclopedia. - 1982-1984.

See what "Saliva" is in other dictionaries:

Saliva, saliva, saliva, saliva, saliva, saliva, saliva, saliva, saliva, saliva, saliva, saliva, saliva (Source: "Full accentuated paradigm according to A. A. Zaliznyak") ... Forms of words

Transparent viscous secretion of the salivary glands, secreted into the oral cavity. The composition of saliva includes water (98.5 99.5%) and inorganic substances dissolved in it. and organic connections. S. has a slightly acidic or slightly alkaline reaction (pH 5.6–7.6). In a day, a person ... ... Biological encyclopedic dictionary

s; well. Fluid secreted by special glands in the oral cavity of humans and animals and helps to wet and digest food. Swallow saliva. Spit saliva. Abundant with. To spit (also: to speak excitedly, with heat, with anger). ◁… … encyclopedic Dictionary

SALIVA, fluid secreted by the SALIVAL GLANDS into the mouth. In vertebrates, saliva is 99% water, in which small amounts of sodium, potassium, calcium and the enzyme amylase are dissolved. Saliva softens and moistens food, which makes it easier ... ... Scientific and technical encyclopedic dictionary

SALIVA, saliva, pl. no (cf. drool), female. A viscous, slightly turbid, viscous liquid secreted in the oral cavity of a person and an animal by special glands, wetting food and thereby contributing to its digestion. Salivation. Swallow saliva. Abundant… … Explanatory Dictionary of Ushakov

saliva- SALIVA1, s, g Fluid secreted by special glands in the oral cavity of humans and animals and promotes wetting and digestion of food. “With sugar!” Elya thought and swallowed her saliva, but the saliva did not moisten her throat, it got stuck in it so dryly (V. Ast ... Explanatory dictionary of Russian nouns

SALIVATION, s, wives. A colorless liquid secreted in the oral cavity of humans and animals that wets food during chewing. Abundant with. To splash with saliva (also translation: to speak excitedly, with heat, with anger). | adj. salivating, oh, oh. Salivary glands.… … Explanatory dictionary of Ozhegov

SALIVA, drool, etc. see sleen. Dahl's Explanatory Dictionary. IN AND. Dal. 1863 1866 ... Dahl's Explanatory Dictionary

Foam, secret Dictionary of Russian synonyms. saliva n., number of synonyms: 3 foam (12) secret ... Synonym dictionary

saliva- is a colorless liquid, pouring, consisting of water, mineral components, organic substances (mucin) and diastase, ptyalin or salivary amylase. Salivation occurs constantly, but increases at the time of eating as a reflex ... ... Universal additional practical explanatory dictionary by I. Mostitsky

saliva- saliva, genus. saliva and obsolete saliva, gen. saliva... Dictionary of pronunciation and stress difficulties in modern Russian

Books

• Saliva. Analytical possibilities and prospects, Vavilova Tatyana Pavlovna, Yanushevich Oleg Olegovich, Ostrovskaya IG This monograph presents current information about the functions of mixed saliva, the role of its proteins and peptides in maintaining homeostasis of the oral cavity. Particular attention is paid to the specifics of the study ...

Digestion begins already in the oral cavity in the form of mechanical processing of food and wetting it with saliva. Saliva is an important component that prepares the food bolus for further digestion. It can not only moisturize food, but also disinfect. Saliva also contains many enzymes that begin to break down simple components even before food is processed by gastric juice.

• Water. Makes up more than 98.5% of the total secret. All active substances are dissolved in it: enzymes, salts and more. The main function is to moisten food and dissolve the substances in it to facilitate the further movement of the food bolus through the gastrointestinal tract and digestion.
• Salts of various acids (trace elements, alkali metal cations). They are a buffer system that is able to maintain the necessary acidity of the food bolus before it enters the stomach environment. Salts can increase the acidity of food in case of its insufficiency or alkalinize it in case of excessively high acidity. With pathology and an increase in salt content, they can be deposited in the form of stones with the formation of gingivitis.
• Mucin. A substance that has adhesive properties, which allows you to collect food into a single lump, which will then move in one conglomerate through the entire gastrointestinal tract.
• Lysozyme. Natural protector with bactericidal properties. Able to disinfect food, provides protection of the oral cavity from pathogens. If the component is insufficient, pathologies such as caries, candidiasis can develop.
• Opiorfin. An anesthetic substance that can anesthetize overly sensitive oral mucosa, rich in nerve endings, from mechanical irritation with solid food.
• Enzymes. The enzymatic system is able to start the digestion of food and prepare it for further processing in the stomach and intestines. The breakdown of food begins with carbohydrate components, since further processing may require energy costs, which provide sugar.

The table shows the content of each component of saliva

saliva enzymes

Amylase

An enzyme capable of breaking down complex carbohydrate compounds, turning them into oligosaccharides, and then into sugar. The main compound that the enzyme acts on is starch. It is thanks to the action of this enzyme that we can feel the sweet taste of the product during its mechanical processing. Further breakdown of starch continues under the action of pancreatic amylase in the duodenum.

Lysozyme

The main bactericidal component, which, in essence, performs its properties due to the digestion of bacterial cell membranes. In fact, the enzyme is also able to break down the polysaccharide chains located in the shell of the bacterial cell, due to which a hole appears in it, through which fluid quickly flows and the microorganism bursts like a balloon.

Maltase

An enzyme capable of breaking down maltose is a complex carbohydrate compound. This produces two molecules of glucose. It acts in combination with amylase up to the small intestine, where it is replaced by intestinal maltase in the duodenum.

Lipase

Saliva contains lingual lipase, which first begins the processing of complex fatty compounds. The substance it acts on is triglyceride, after being treated with an enzyme, it is broken down into glycerol and fatty acids. Its action ends in the stomach, where gastric lipase comes to replace it. For children, it is lingual lipase that is of greater importance, since the first one begins the digestion of milk fats in breast milk.

Proteases

The conditions necessary for adequate digestion of proteins are absent in saliva. They are able to break down only already denatured protein components into simpler ones. The main process of protein digestion begins after the denaturation of protein chains under the action of hydrochloric acid in the intestine. However, the proteases contained in saliva are also very important for the normal digestion of food.

Other elements

Other elements include no less important compounds that ensure the correct formation of the food bolus. This process is important as the beginning of adequate and complete digestion.

Mucin

A sticky substance that is able to gather together a food bolus. Its action continues until the release of processed food from the intestinal tract. It contributes to the uniform digestion of chyme, and thanks to the mucus-like consistency, it greatly facilitates and softens its movement along the tract. The substance also performs a protective function by enveloping the gums, teeth, and mucous membranes, which significantly reduces the traumatic effect of solid unprocessed food on delicate structures. In addition, the sticky consistency promotes the adhesion of disease-causing agents, which are subsequently destroyed by lysozyme.

Opiorfin

A natural antidepressant, a neurogenic mediator that can act on nerve pain endings, blocking the transmission of pain impulses. This allows you to make the chewing process painless, although hard particles often injure the mucous membrane, gums, and the surface of the tongue. Naturally, microdoses are released in saliva. There is a theory that the pathogenetic mechanism is an increase in the release of opiate, due to the dependence that is formed in humans, the need for irritation of the oral cavity increases, an increase in the secretion of saliva - and therefore opiorphin.

Buffer systems

Various salts that provide the necessary acidity for the normal functioning of the enzyme system. They also create the necessary charge on the surface of the chyme, which contributes to the stimulation of peristaltic waves, mucus of the internal mucous membrane lining the gastrointestinal tract. Also, these systems contribute to the mineralization of tooth enamel and its strengthening.

epidermal growth factor

A protein hormonal compound that promotes the launch of regenerative processes. Cell division of the oral mucosa occurs at lightning speed. This is understandable, since they are damaged much more often than any other, as a result of mechanical stress and bacterial attacks.

• Protective. It consists in disinfecting food and protecting the oral mucosa and tooth enamel from mechanical damage.
• Digestive. Enzymes contained in saliva begin digestion already at the stage of grinding food.
• Mineralizing. Allows you to strengthen tooth enamel, due to solutions of salts contained in saliva.
• Cleansing. The abundant secretion of saliva contributes to the self-cleaning of the oral cavity, due to its washing.
• Antibacterial. The components of saliva have a bactericidal property, due to which many pathogens do not penetrate beyond the oral cavity.
• excretory. Saliva contains metabolic products (such as ammonia, various toxins, including medicinal ones), when spitting out, the body gets rid of toxins.
• Anesthetic. Due to the content of opiorphin, saliva is able to temporarily anesthetize small cuts, and also provides painless food processing.
• Speech. Thanks to the water component, it provides moisture to the oral cavity, which helps articulate speech.
• Healing. Due to the content of the epidermal growth factor, it promotes the fastest healing of all wound surfaces, therefore, reflexively, with any cut, we try to lick the wound.

The excretory ducts of three pairs of large salivary glands open into the oral cavity: parotid, submandibular and sublingual. In addition to them, in the oral mucosa there are numerous small glands, which are called by their location: labial, buccal, palatine and lingual. In the area of ​​​​the tongue are located: the anterior salivary gland on the lower surface of the tip of the tongue, on the root of the tongue - glands, the ducts of which flow into the gaps between the foliose and zholobovidny papillae. The excretory ducts of the labial, buccal glands open on the eve of the mouth, and the submandibular, sublingual, palatine and lingual glands open into the oral cavity proper. By the nature of the secretion, the glands are divided into protein, mucous and mixed.

Saliva is a mixture of the secretions of three large and many small salivary glands. Epithelial cells, food particles, salivary bodies (neutrophilic leukocytes, lymphocytes), mucus, and microorganisms are mixed with the secretion secreted in the oral cavity.

Composition and properties of saliva.

The salivary gland secretion contains 98-99% water, and the rest is a solid residue, which includes mineral anions of chlorides, phosphates, bicarbonates, iodides, bromides, fluorides, sulfates. Saliva contains sodium, potassium, calcium, magnesium cations and trace elements - iron, copper, nickel, lithium and others. The concentration of substances such as iodine, potassium, strontium is much higher than in the blood. Organic substances are represented mainly by proteins (albumins, globulins, enzymes), but besides them, there are also nitrogen-containing components in saliva (urea, ammonia, creatinine, free amino acids, gamma-aminoglutaminate, taurine, phosphoethanolamine, hydroxyproline, vitamins). Some of these substances pass into the saliva from the blood plasma unchanged, and some (amylase, glycoproteins) are synthesized in the salivary glands.

Large and small salivary glands normally secrete a secret of different composition and quantity. The parotid glands secrete liquid saliva containing a large amount of potassium and sodium chlorides, enzymes - catalase (hydrolyzes hydrogen peroxide to water and oxygen) and amylase. The latter has calcium in its composition, without which it does not work. Amylase needs chloride ions to perform its functions. There is no alkaline phosphatase in this secret, but the activity of acid phosphatase is very high.

The submandibular glands secrete a product that contains a large amount of organic substances (mucin, amylase) and a small amount of potassium thiocyanate. Of the mineral substances, salts of sodium chloride, calcium chloride, calcium phosphate, and magnesium phosphate predominate. Amylase is much less than in the secretion of the parotid gland.

The sublingual glands secrete saliva rich in mucin and have a strong alkaline reaction. The activity of alkaline and acid phosphatases in this saliva is very high. The consistency of saliva is viscous and sticky.

In the oral cavity, saliva performs a digestive function, and in addition, it has a protective and trophic function for tooth enamel. The digestive function is to prepare a portion of food for swallowing and digestion. Chewed food is mixed with saliva, which is 10-12% of its amount. Mucin contributes to the formation of a food lump and swallowing, it is the most important organic component of saliva.

In the oral cavity, saliva acts as a digestive juice. It consists of about 50 enzymes that belong to the classes of hydrolases, oxidoreductases, transferases.

The protective function of saliva is that it protects the mucous membrane and teeth from drying out, physical and chemical damage by food, equalizes the temperature of food, binds acids as an amphoteric buffer and washes plaque from the teeth, promotes self-cleaning of the oral cavity and teeth; the presence of lysozyme, an enzyme-like protein that has bactericidal properties, gives it the opportunity to take part in the body's defense reactions and in the processes of regeneration of the epithelium in case of damage to the oral mucosa.

• Water (about 99% of the total composition of saliva). Provides wetting and dissolution of food components for the appearance of a sense of taste and primary digestive reactions. Moisturizes the mouth. Promotes speech.
• Bicarbonates. Maintain a slightly alkaline reaction of saliva (pH: 5.25-8.0).
• Chlorides. Activate salivary amylase, an enzyme that breaks down starch.
• Immunoglobulin A (IgA) An integral part of the salivary antibacterial system.
• Lysozyme. Bactericidal enzyme, prevents caries, takes part in the processes of regeneration of the epithelium of the oral mucosa
• Mucin. Glycoprotein, which promotes the formation of mucus and the formation of a food bolus.
• Slime. Participates in the formation of a food lump. Promotes swallowing. Provides buffer properties of saliva.
• Phosphates. Maintain saliva pH.
• Salivary alpha-amylase (ptyalin). Catalyzes the breakdown of polysaccharides to disaccharides
• Urea, uric acid. He perform digestive functions; are products of excretion.
• Maltase (glucosidase). Breaks down maltose and sucrose into monosaccharides.

Human saliva is a colorless and transparent biological liquid of an alkaline reaction, which is secreted by three large salivary glands: submandibular, sublingual and parotid, and many small glands located in the oral cavity. Its main components are water (98.5%), trace elements and alkali metal cations, as well as acid salts. Wetting the oral cavity, it helps free articulation, protects tooth enamel from mechanical, thermal and cold effects. Under the influence of salivary enzymes, it starts the process of digestion of carbohydrates.

The protective function of saliva is manifested in the following:

• Protection of the oral mucosa from drying out.
• Neutralization of alkalis and acids.
• Due to the content of the protein substance lysozyme in saliva, which has a bacteriostatic effect, regeneration of the epithelium of the oral mucosa occurs.
• Nuclease enzymes, also found in saliva, help protect the body from viral infections.
• Saliva contains enzymes (antithrombins and antithrombinoplastins) that prevent blood clotting.
• Many immunoglobulins contained in saliva protect the body from the possibility of penetration of pathogens.

The digestive function of saliva is to wet the food bolus and prepare it for swallowing and digestion. All this is facilitated by the mucin that is part of the saliva, which glues food into a lump.

Food is present in the oral cavity for an average of about 20 seconds, but despite this, digestion, which begins in the oral cavity, significantly affects the further breakdown of food. After all, when saliva dissolves food substances, it forms taste sensations and largely affects the awakening of appetite.

The chemical processing of food also takes place in the oral cavity. Under the influence of amylase (saliva enzyme), polysaccharides (glycogen, starch) are broken down to maltose, and the next saliva enzyme, maltase, breaks down maltose to glucose.

excretory function. Saliva has the ability to excrete metabolic products of the body. For example, some drugs, uric acid, urea, or salts of mercury and lead can be excreted with saliva. All of them leave the human body at the time of spitting saliva.

trophic function. Saliva is a biological medium that has direct contact with tooth enamel. It is she who is the main source of zinc, phosphorus, calcium and other trace elements necessary for the preservation and development of teeth.

Recently, the importance of saliva has become even greater - now it is used to diagnose various diseases not only of the oral cavity, but of the whole organism. All that is needed is to collect a few drops of saliva on a cotton swab. Next, a test is carried out, which can reveal the presence of diseases of the oral cavity, the level of alcohol content, the hormonal state of the body, the presence or absence of HIV, and many other indicators of human health.

This test does not bring the patient absolutely no discomfort. Moreover, you can conduct research at home by buying special kits in a pharmacy, which are designed for self-sampling of saliva analysis. After that, it remains only to send them to the laboratory and wait for the results.

• The process of salivation is divided into conditioned reflex and unconditional reflex mechanism. The conditioned reflex process can be caused by any kind, smell of food, sounds associated with its preparation, or by talking and remembering food. The unconditioned reflex process of salivation occurs already in the process of food entering the oral cavity.
• With insufficient saliva, food debris is not completely washed out of the oral cavity, which leads to yellow staining of the teeth.
• The process of salivation decreases when fright or stress occurs, and stops altogether during sleep or anesthesia.
• 0.5 - 2.5 liters is the amount of saliva secreted per day, which is necessary for the normal functioning of the human body.
• If a person is in a calm state, then the rate of saliva secretion does not exceed 0.24 ml / min, and in the process of chewing food, it increases to 200 ml / min.
• In people over 55, the salivation process slows down.
• Insect bites are less painful and pass faster if they are moistened with saliva from time to time.
• Saliva lotions are used to get rid of warts, abscesses and various types of inflammation on the skin, up to ringworm.
• An increased dose of sugar in the blood negatively affects the secretion of saliva.

The quality of saliva and the presence of useful properties in it directly depends on the general condition of the oral cavity, as well as on the health of teeth and gums in particular. So