Innervation of the salivary glands. Secretory function of the salivary glands. Sympathetic nervous system
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It is located in the submandibular triangle, but in some people it extends beyond the tendon of the digastric muscle (Fig. 1.20).
The upper edge of the gland is adjacent to the lower jaw, and the upper surface is adjacent to the mylohyoid muscle. Having rounded the posterior edge of the said muscle, the gland is located on its upper surface and comes into contact with the posterior outer surface of the sublingual salivary gland (SJ).
The posterior edge of the submandibular SG reaches the capsule of the parotid SG and the medial pterygoid muscle.
The excretory duct begins from the upper inner edge of the gland, then penetrates into the gap between the mylohyoid and hyoid-glossus muscles. Along the inner surface of the sublingual salivary gland, the excretory duct runs anteriorly and upward and opens in the anterior part of the floor of the mouth on the sublingual papilla.
Rice. 1.20. Submandibular salivary gland and its relationship with surrounding structures: 1 - parotid salivary gland; 2 - submandibular salivary gland; 3 - additional lobe of the parotid salivary gland; 4 - duct of the parotid salivary gland; 5 - chewing muscle; 6 - sternocleidomastoid muscle; 7 - common facial vein; 8 - superficial temporal artery and vein; 9 - posterior facial vein; 10 - sublingual salivary gland; 11 - sternothyroid muscle; 12 - thyrohyoid muscle; 13 - external maxillary artery and anterior facial vein
The submandibular SG is surrounded on all sides by a capsule, which is formed by the superficial plate of the cervical fascia. The latter, splitting, forms a sheath for the submandibular gland, the outer plate of which is attached to the lower edge of the lower jaw, the inner plate to the line of attachment of the mylohyoid muscle.
Between the submandibular salivary gland and the vagina there is a layer of loose fiber.
The submandibular space is limited from below by the superficial layer of the fascia proper of the neck, from above by the fascial sheath of the mylohyoid muscle, the loose fascia covering the hyoid muscle, and the superior constrictor of the pharynx. From the submandibular space, the pathological process spreads to the anterior part of the peripharyngeal space and the sublingual cellular space.
Aponeurosis
Spread into the parotid cellular space is prevented by a strong aponeurosis running from the sheath of the sternocleidomastoid muscle to the angle of the lower jaw. This enclosed space also contains the facial artery, anterior facial vein, and lymph nodes (Fig. 1.21). The latter collect lymph from the upper and lower lips, oral cavity, tongue, lower jaw, and pharynx.
Rice. 1.21. Schematic representation of the submandibular cellular space:
1 - fascial spur separating the submandibular cellular space from the periandibular cellular space; 2 - mylohyoid muscle; 3 - anterior belly of the digastric muscle; 4 - submandibular salivary gland; 5 - hyoid bone; 6 - lower jaw
The facial artery, being a branch of the external carotid artery, passes into the submandibular triangle from under the posterior belly of the digastric muscle and the stylohyoid muscle and penetrates the submandibular SG at its posterior edge. At the level of the anterior edge of the masticatory muscle, the facial artery leaves the gland on the face, bending over the edge of the lower jaw (here its pulsation is easy to feel).
The blood supply to the submandibular SG is carried out by the branches of the facial, lingual and mental arteries. The venous network in this area is formed by the anterior facial and retromandibular veins, which flow into the common facial vein.
The anterior facial vein accompanies the facial artery, at the lower edge of the lower jaw it is located behind the artery, penetrates the capsule of the gland and runs along its anterior surface.
In the submandibular sheath, slightly higher (2-8 mm) of the posterior belly of the digastric muscle, the hypoglossal nerve (XII pair of cranial nerves) passes, which accompanies the lingual vein. The sensory lingual nerve passes through the upper part of the submandibular triangle.
Innervation of the submandibular salivary gland is carried out chorda tympani(from the facial nerve) through the submandibular ganglion and the sympathetic nerves accompanying the facial artery. The outflow of lymph occurs to the lymph nodes at the lower pole of the parotid gland and to the deep jugular lymph nodes.
The sublingual SG is located directly under the mucous membrane of the floor of the mouth on the maxillary-hyoid muscle, lateral to the geniohyoid, genioglossus and hyoid-glossus muscles, lifting the mucous membrane under the tongue in the form of a roller (Fig. 1.22). The sublingual SG is surrounded by connective tissue and does not have a capsule. The anterior part of the gland is adjacent to the inner surface of the body of the lower jaw, the posterior part is adjacent to the submandibular gland.
Rice. 1.22. Sublingual salivary gland: 1 - small ducts of the sublingual gland; 2 - sublingual papilla; 3 - large sublingual duct; 4 - submandibular SG; 5 - duct of the submandibular SG; 6 - sublingual SG
The duct of the sublingual gland passes along the inner surface of the sublingual gland, which opens in the anterior part of the floor of the mouth, on the sides of the frenulum of the tongue in the sublingual papilla, independently or by connecting with the duct of the submandibular gland (Wharton's duct). Numerous small ducts open along the sublingual fold (Fig. 1.23). In the sublingual space there are five intermuscular gaps, through which the pathological process quickly spreads to neighboring structures (Fig. 1.24).
Rice. 1.23. Ducts of the sublingual fluid along the sublingual fold: 1 - sublingual fold with ducts opening on it; 2 - sublingual papilla; 3 - duct of the submandibular SG; 4 - submandibular SG; 5 - lingual nerve; 6 - anterior lingual gland
The sublingual space along the sublingual duct and the process of the submandibular SG communicates with the cellular space of the submandibular and mental regions. Outside and anterior to the sublingual gland there is the space of the maxillo-lingual groove, where the lingual nerve, the duct of the submandibular gland with the surrounding lobe of the gland and the hypoglossal nerve with the lingual vein pass. This is the weakest place in the sublingual space.
Rice. 1.24. Scheme of the sublingual tissue space: 1 - mucous membrane of the tongue; 2 - lingual vessels and nerves; 3 - sublingual SG; 4 - genioglossus and geniohyoid muscles; 5 - mylohyoid muscle; 6 - lower jaw
The sublingual cellular space also communicates with the anterior parapharyngeal space via the stylohyoid muscle and its special sheath. Blood supply is provided by the branches of the facial artery. Venous outflow is carried out through the sublingual vein.
Lymph drainage occurs in the submandibular and mental lymph nodes.
Minor salivary glands
There are mucous, serous and mixed small SGs, which lie singly and in groups in the submucosal layer, in the thickness of the mucous membrane and between muscle fibers in the oral cavity, oropharynx, and upper respiratory tract. They are clusters of glandular cells that form parenchyma, consisting of lobules separated by connective tissue. Numerous excretory ducts pierce the mucous membrane and pour out their secretions.The largest clusters of lingual glands (anterior lingual gland) are located on either side of the tip of the tongue. Excretory ducts open on the lower surface of the tongue along the fimbriated fold.
Rice. 1.25. Salivary glands of the tongue (photo of the specimen by Y.R. Sinelnikov): a: 1 - glands of the region of the foliate papillae; 2 - glands of the region of the circumvallate papillae; 3 - filiform papillae; 4 - glands of the root of the tongue; b - isolated glands
Some of the glands can be located deep in the muscles of the posterior part of the body of the tongue and open in the folds of the leaf-shaped papillae. In the area of the lingual tonsil, the glands are located under the mucous membrane in a layer of 4-8 mm and can extend to the epiglottis. Their ducts open into depressions in and around the middle of the follicles.
The serous glands in the region of the circumvallate and foliate papillae of the tongue open into the folds between the papillae and into the grooves surrounding the circumvallate papillae (Fig. 1.25).
Rice. 1.26. Labial and buccal glands (photo of the specimen by E. Kovbasy): a: 1 - upper lip; 2 - lower lip; 3.4 - left and right cheek; b - isolated gland
The labial glands lie in the submucosal layer, have a round shape, and measure up to 5 mm. The buccal glands lie in small numbers in the submucosal layer and between the muscle bundles of the buccal muscle. The glands of the cheek, located in the area of the last large molar (molar), are called molar.
Between the mucous membrane of the palate and the periosteum there is a thin layer of mucous palatine glands, filling the space between the bony palate and the alveolar processes.
Rice. 1.27. Salivary glands of the hard and soft palate: 1 - salivary glands of the hard and soft palate; 2 - great palatine artery; 3 - parotid SG duct; 4 - muscle that lifts the velum palatine; 5 - buccal part of the pharyngeal constrictor; 6 - velopharyngeal muscle; 7 - palatine tonsil; 8 - pharynx; 9 - uvula
The layer of glands thickens towards the soft palate and passes into the glands of the soft palate, located in the mucous membrane (Fig. 1.27). The pharyngeal glands lie in the submucosal layer of the pharynx and open on the mucous membrane (Fig. 1.28).
Rice. 1.28. Salivary glands of the pharynx (photo of the specimen by V. Malishevskaya): a - group of glands; b - isolated gland
Nasal glands of a mucous nature lie in the mucous membrane of the nasal cavity and paranasal sinuses. An accumulation of mucous laryngeal glands is present throughout the larynx, especially in the area of the ventricles of the larynx, on the posterior surface of the epiglottis and in the interarytenoid region. Glands are absent at the edges of the vocal folds (Fig. 1.29).
Rice. 1.29. Salivary glands of the larynx (photo of the preparation by P. Ruzhinsky): a - group of glands; b - isolated gland
The mucous glands of these organs lie predominantly in the submucosal layer in the area of the intercartilaginous spaces and the membranous part of the trachea and bronchi, and in smaller quantities behind the cartilages (Fig. 1.30).
Rice. 1.30. Salivary glands of the trachea (photo of the specimen by Ya. R. Sinelnikov)
A.I. Paches, T.D. Tabolinovskaya
The neurons from which preganglionic fibers arise are located in the lateral horns of the spinal cord at the level Th II - T VI. These fibers approach the superior cervical ganglion (gangl. cervicale superior), where they end on postganglionic neurons that give rise to axons. These postganglionic nerve fibers, together with the choroid plexus accompanying the internal carotid artery (plexus caroticus internus), reach the parotid salivary gland and, as part of the choroid plexus surrounding the external carotid artery (plexus caroticus externus), the submandibular and sublingual salivary glands.
Parasympathetic fibers play a major role in regulating salivary secretion. Irritation of parasympathetic nerve fibers leads to the formation of acetylcholine in their nerve endings, which stimulates the secretion of glandular cells.
Sympathetic fibers of the salivary glands are adrenergic. Sympathetic secretion has a number of features: the amount of saliva released is significantly less than during irritation of the chorda tympani, saliva is released in rare drops, and it is thick. In humans, stimulation of the sympathetic trunk in the neck causes secretion from the submandibular gland, while no secretion occurs in the parotid gland.
Salivary centers The medulla oblongata consists of two symmetrically located neuronal pools in the reticular formation. The rostral part of this neural formation - the superior salivary nucleus - is connected with the submandibular and sublingual glands, the caudal part - the inferior salivary nucleus - with the parotid gland. Stimulation in the area located between these nuclei causes secretion from the submandibular and parotid glands.
The diencephalic region plays an important role in the regulation of salivation. When the anterior hypothalamus or preoptic area (thermoregulation center) is stimulated in animals, the heat loss mechanism is activated: the animal opens its mouth wide, shortness of breath and salivation begin. When the posterior hypothalamus is stimulated, strong emotional arousal and increased salivation occur. Hess (Hess, 1948), when stimulating one of the zones of the hypothalamus, observed a picture of eating behavior, which consisted of movements of the lips, tongue, chewing, salivation and swallowing. The amygdala has close anatomical and functional connections with the hypothalamus. Specifically, stimulation of the amygdala complex causes the following food reactions: licking, sniffing, chewing, salivation and swallowing.
The secretion of saliva, obtained by irritation of the lateral hypothalamus, after removal of the frontal lobes of the cerebral cortex increases significantly, which indicates the presence of inhibitory influences of the cerebral cortex on the hypothalamic sections of the salivary center. Salivation can also be caused by electrical stimulation of the olfactory brain (rhinencephalon).
In addition to the nervous regulation of the work of the salivary glands, a certain influence on their activity of sex hormones, hormones of the pituitary gland, pancreas and thyroid glands has been established.
Some chemicals can stimulate or, conversely, inhibit the secretion of saliva, acting either on the peripheral apparatus (synapses, secretory cells) or on the nerve centers. Copious secretion of saliva is observed during asphyxia. In this case, increased salivation is a consequence of irritation of the salivary centers with carbonic acid.
The influence of some pharmacological substances on the salivary glands is associated with the mechanism of transmission of nervous influences from parasympathetic and sympathetic nerve endings to the secretory cells of the salivary glands. Some of these pharmacological substances (pilocarpine, proserine and others) stimulate salivation, while others (for example, atropine) inhibit or stop it.
Mechanical processes in the oral cavity.
The upper and lower ends of the digestive tract differ from other parts in that they are relatively fixed to the bones and consist not of smooth, but mainly of striated muscle. Food enters the oral cavity in the form of pieces or liquids of varying consistency. Depending on this, it either immediately passes into the next section of the digestive tract, or is subjected to mechanical and initial chemical treatment.
Chewing. The process of mechanical processing of food - chewing - consists of grinding its solid components and mixing with saliva. Chewing also helps evaluate the taste of food and is involved in the stimulation of salivary and gastric secretions. Since chewing mixes food with saliva, it facilitates not only swallowing, but also partial digestion of carbohydrates by amylase.
The act of chewing is partly reflexive, partly voluntary. When food enters the oral cavity, the receptors of its mucous membrane (tactile, temperature, taste) are irritated, from where impulses are transmitted along the afferent fibers of the trigeminal nerve to the sensory nuclei of the medulla oblongata, the nuclei of the optic thalamus, and from there to the cerebral cortex. From the brain stem and thalamus opticus, collaterals extend to the reticular formation. The motor nuclei of the medulla oblongata, red nucleus, substantia nigra, subcortical nuclei and cerebral cortex take part in the regulation of chewing. These structures are chewing center. Impulses from it travel through motor fibers (mandibular branch of the trigeminal nerve) to the masticatory muscles. In humans and most animals, the upper jaw is motionless, so chewing is reduced to movements of the lower jaw, carried out in the following directions: from top to bottom, from front to back and sideways. The muscles of the tongue and cheeks play an important role in holding food between the chewing surfaces. Regulation of the movements of the lower jaw to carry out the act of chewing occurs with the participation of proprioceptors located in the thickness of the masticatory muscles. Thus, the rhythmic act of chewing occurs involuntarily: The ability to chew consciously and regulate this function at an involuntary level is presumably associated with the representation of the act of chewing in the structures of various levels of the brain.
When registering chewing (masticationography), the following phases are distinguished: rest, introducing food into the mouth, indicative, main, formation of a food bolus. Each of the phases and the entire period of chewing has a different duration and character, which depends on the properties and quantity of food chewed, age, appetite with which food is taken, individual characteristics, the usefulness of the masticatory apparatus and its control mechanisms.
Swallowing. According to Magendie's theory (Magendie, 1817), the act of swallowing is divided into three phases - oral free pharyngeal involuntary, fast and esophageal, also involuntary, but slow. From the crushed food mass moistened with saliva in the mouth, a food bolus is separated, which, with the movements of the tongue, moves towards the midline between the front of the tongue and the hard palate. At the same time, the jaws compress and the soft palate rises. Together with the contracted velopharyngeal muscles, it forms a septum that blocks the passage between the mouth and the nasal cavity. To move the bolus of food, the tongue moves backward, pressing on the palate. This movement moves the lump into the throat. At the same time, intraoral pressure increases and helps push the food bolus in the direction of least resistance, i.e. back. The entrance to the larynx is closed by the epiglottis. At the same time, compression of the vocal cords also closes the glottis. As soon as a lump of food enters the pharynx, the anterior arches of the soft palate contract and, together with the root of the tongue, prevent the lump from returning to the oral cavity. Thus, when the muscles of the pharynx contract, a bolus of food can only be pushed into the opening of the esophagus, which is expanded and moved towards the pharyngeal cavity.
Changes in pharyngeal pressure during swallowing also play an important role. The pharyngoesophageal sphincter is usually closed before swallowing. During swallowing, the pressure in the pharynx increases sharply (up to 45 mm Hg). When the high pressure wave reaches the sphincter, the sphincter muscles relax and the pressure in the sphincter quickly decreases to the level of external pressure. Thanks to this, the lump passes through the sphincter, after which the sphincter closes, and the pressure in it increases sharply, reaching 100 mm Hg. Art. At this time, the pressure in the upper part of the esophagus reaches only 30 mm Hg. Art. The significant difference in pressure prevents the bolus of food from refluxing from the esophagus into the pharynx. The entire swallowing cycle lasts approximately 1 second.
This entire complex and coordinated process is a reflex act, which is carried out by the activity of the swallowing center of the medulla oblongata. Since it is located close to the respiratory center, breathing stops every time the act of swallowing occurs. The movement of food through the pharynx and through the esophagus into the stomach occurs as a result of successively occurring reflexes. During the implementation of each link in the chain of the swallowing process, irritation of the receptors embedded in it occurs, which leads to a reflex inclusion of the next link in the act. Strict coordination of the components of the act of swallowing is possible due to the presence of complex relationships between various parts of the nervous system, starting from the medulla oblongata and ending with the cerebral cortex.
The swallowing reflex occurs when irritation of the sensory receptor endings of the trigeminal nerve, superior and inferior laryngeal and glossopharyngeal nerves embedded in the mucous membrane of the soft palate. Along their centripetal fibers, excitation is transmitted to the swallowing center, from where impulses propagate along the centrifugal fibers of the upper and lower pharyngeal, recurrent and vagus nerves to the muscles involved in swallowing. The swallowing center operates on an “all or nothing” principle. The swallowing reflex occurs when afferent impulses reach the swallowing center in a uniform row.
A slightly different mechanism for swallowing liquids. When drinking by retracting the tongue without breaking the lingual-palatal bridge, negative pressure is formed in the oral cavity and the liquid fills the oral cavity. Then the contraction of the muscles of the tongue, the floor of the mouth and the soft palate creates such a high pressure that, under its influence, the liquid is injected into the esophagus, which is relaxing at this moment, reaching the cardia almost without the participation of contraction of the pharyngeal constrictors and esophageal muscles. This process takes place within 2-3 seconds.
Table of contents of the topic "Autonomic (autonomic) nervous system.":1. Autonomic (autonomic) nervous system. Functions of the autonomic nervous system.
2. Autonomic nerves. Exit points of autonomic nerves.
3. Reflex arc of the autonomic nervous system.
4. Development of the autonomic nervous system.
5. Sympathetic nervous system. Central and peripheral divisions of the sympathetic nervous system.
6. Sympathetic trunk. Cervical and thoracic sections of the sympathetic trunk.
7. Lumbar and sacral (pelvic) sections of the sympathetic trunk.
8. Parasympathetic nervous system. The central part (division) of the parasympathetic nervous system.
9. Peripheral division of the parasympathetic nervous system.
10. Innervation of the eye. Innervation of the eyeball.
12. Innervation of the heart. Innervation of the heart muscle. Innervation of the myocardium.
13. Innervation of the lungs. Innervation of the bronchi.
14. Innervation of the gastrointestinal tract (intestine to the sigmoid colon). Innervation of the pancreas. Innervation of the liver.
15. Innervation of the sigmoid colon. Innervation of the rectum. Innervation of the bladder.
16. Innervation of blood vessels. Innervation of blood vessels.
17. Unity of the autonomic and central nervous systems. Zones Zakharyin - Geda.
The afferent pathway for the lacrimal gland is n. lacrimalis(branch of n. ophthalmicus from n. trigemini), for the submandibular and sublingual - n. lingualis (branch of n. mandibularis from n. trigemini) and chorda tympani (branch of n. intermedius), for the parotid - n. auriculotemporal and n. glossopharyngeus.
Efferent parasympathetic innervation of the lacrimal gland. The center lies in the upper part of the medulla oblongata and is connected with the nucleus of the intermediate nerve (nucleus salivatorius superior). Preganglionic fibers are part of n. intermedius, then n. petrosus major to ganglion pterygopalatinum. This is where the postganglionic fibers begin, which are part of n. maxillaris and further its branches, n. zygoma ticus, through connections with n. lacrimalis reach the lacrimal gland.
Efferent parasympathetic innervation of the submandibular and sublingual glands. Preganglionic fibers come from the nucleus salivatorius superior as part of n. intermedius, then chorda tympani and n. lingualis to the ganglion submandibulare, from where the spinal glionic fibers begin, reaching the glands.
Efferent parasympathetic innervation of the parotid gland. Preganglionic fibers come from the nucleus salivatorius inferior as part of n. glossopharyngeus, then n. tympanicus, n. petrosus minor to ganglion oticum. This is where the postganglionic fibers begin, going to the gland as part of n. auriculotemporalis. Function: increased secretion of the lacrimal and named salivary glands; dilation of gland vessels.
Efferent sympathetic innervation of all these glands. Preganglionic fibers begin in the lateral horns of the upper thoracic segments of the spinal cord and end in the superior cervical ganglion of the sympathetic trunk. Postganglionic fibers begin in the named node and reach the lacrimal gland as part of the plexus caroticus internus, to the parotid gland as part of the plexus caroticus externus, and to the submandibular and sublingual glands through the plexus caroticus externus and then through the plexus facialis. Function: delayed saliva secretion (dry mouth); lacrimation (not a drastic effect).
Sympathetic nervous system
Its function is adaptive trophic (changes the level of metabolism in organs depending on the function they perform in certain environmental conditions).
It is divided into a central and peripheral section.
The central section is thoracolumbar, as it is located in the lateral horns of the spinal cord from the 8th cervical to the 3rd lumbar segment of the spinal cord.
These nuclei are called nucleus intermediolateralis.
Peripheral department.
This includes:
1) rami communicantes albi et grisei
2) nodes of 1st and 2nd order
3) plexuses
1) Nodes of the 1st order are ganglia trunci sympathici or nodes of the sympathetic trunks, which run from the base of the skull to the coccyx. These nodes are divided into groups: cervical, thoracic, lumbar and sacral.
Cervical - in these nodes there is a switching of nerve fibers for the organs of the head, neck and heart. There are 3 cervical nodes: ganglion cervicale superius, medium, inferius.
Thoracic - there are only 12 of them. Nerve fibers are switched in them to innervate the organs of the thoracic cavity.
Nodes of the 2nd order - are located in the abdominal cavity in those places where unpaired visceral arteries depart from the aorta, these include 2 celiac nodes (ganglia celiaci), 1 superior mesenteric node (ganglion mesentericum superius),
1 inferior mesenteric (mesentericum inferius)
Both celiac and superior mesenteric nodes belong to the solar plexus and are needed for the innervation of the abdominal organs.
The inferior mesenteric node is needed to innervate the pelvic organs.
2) Rami communicantes albi - connect the spinal nerves to the nodes of the sympathetic trunk and are part of the preganglionic fibers.
There are a total of 16 pairs of white connecting branches.
Rami communicantes grisei - connect nodes with nerves, they are part of postganglionic fibers, there are 31 pairs of them. They innervate the soma and belong to the somatic part of the sympathetic nervous system.
3) Plexuses - they are formed by postganglionic fibers around the arteries.
* Response plan for organ innervation
1. Center of innervation.
2. Preganglionic fibers.
3. The node in which the switching of nerve fibers occurs.
4. Postgangionary fibers
5. Effect on the organ.
Sympathetic innervation of the salivary glands
1. The center of innervation is located in the spinal cord in the lateral horns in the nucleus intermediolateralis of the first two thoracic segments.
2. Preganglinar fibers are part of the anterior root, spinal nerve and ramus communicans albus
3. Switching to ganglion cervicale superius.
4. Postganglionic fibers form the plexus caroticus externus
5. Decreased secretion.
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Submandibular gland,glandula submandibularis, is a complex alveolar-tubular gland that secretes a secretion of a mixed nature. Located in the submandibular triangle, covered with a thin capsule. Outside the gland is adjacent to the superficial plate of the cervical fascia and skin. The medial surface of the gland is adjacent to the hyoglossus and styloglossus muscles, at the top of the gland it is in contact with the inner surface of the body of the lower jaw, its lower part emerges from under the lower edge of the latter. The anterior part of the gland in the form of a small process lies on the posterior edge of the mylohyoid muscle. Here its submandibular duct emerges from the gland, ductus submandibularis (Wharton's duct), which is directed forward, is adjacent on the medial side to the sublingual salivary gland and opens with a small opening on the sublingual papilla, next to the frenulum of the tongue. On the lateral side, the facial artery and vein are adjacent to the gland until they bend through the lower edge of the lower jaw, as well as the submandibular lymph nodes. Vessels and nerves of the submandibular gland. The gland receives arterial branches from the facial artery. Venous blood flows into the vein of the same name. Lymphatic vessels drain into the adjacent submandibular nodes. Innervation: sensitive - from the lingual nerve, parasympathetic - from the facial nerve (VII pair) through the chorda tympani and submandibular ganglion, sympathetic - from the plexus around the external carotid artery.
Sublingual gland,glandula sublingualis, small in size, secretes a mucous type secretion. It is located on the upper surface of the mylohyoid muscle, directly under the mucous membrane of the floor of the mouth, which forms the sublingual fold here. The lateral side of the gland is in contact with the inner surface of the lower jaw in the area of the hyoid fossa, and the medial side is adjacent to the geniohyoid, hyoglossus and genioglossus muscles. Greater hypoglossal duct ductus sublingualis major, opens together with the excretory duct of the submandibular gland (or independently) on the sublingual papilla.
Several small sublingual ducts duc tus sublingudles minores, flow into the oral cavity independently on the surface of the mucous membrane along the sublingual fold.
Vessels and nerves of the sublingual gland. TO The gland is supplied by branches of the hypoglossal artery (from the lingual artery) and the mental artery (from the facial artery). Venous blood flows through the veins of the same name. The lymphatic vessels of the gland drain into the submandibular and mental lymph nodes. Innervation: sensitive - from the lingual nerve, parasympathetic - from the facial nerve (VII pair) through the chorda tympani and submandibular ganglion, sympathetic - from the plexus around the external carotid artery.
47. Parotid salivary gland: topography, structure, excretory duct, blood supply and innervation.
parotid gland,glandula parotidea, is a gland of the serous type, its weight is 20-30 g. It is the largest of the salivary glands and has an irregular shape. It is located under the skin anterior and inferior to the auricle, on the lateral surface of the ramus of the mandible and the posterior edge of the masticatory muscle. The fascia of this muscle is fused with the capsule of the parotid salivary gland. At the top, the gland almost reaches the zygomatic arch, at the bottom - to the angle of the lower jaw, and at the back - to the mastoid process of the temporal bone and the anterior edge of the sternocleidomastoid muscle. In the depths, behind the lower jaw (in the maxillary fossa), the parotid gland with its deep part, pars profunda, adjacent to the styloid process and the muscles starting from it: stylohyoid, styloglossus, stylopharyngeal. The external carotid artery, the mandibular vein, the facial and auriculotemporal nerves pass through the gland, and deep parotid lymph nodes are located in its thickness.
The parotid gland has a soft consistency and well-defined lobulation. The outside of the gland is covered with a connecting capsule, bundles of fibers of which extend into the organ and separate the lobules from each other. Excretory parotid duct, ductus parotideus (stenon duct), leaves the gland at its anterior edge, goes forward 1-2 cm below the zygomatic arch along the outer surface of the masticatory muscle, then, going around the anterior edge of this muscle, pierces the buccal muscle and opens on the vestibule of the mouth at the level of the second upper major molar tooth.
In its structure, the parotid gland is a complex alveolar gland. On the surface of the masticatory muscle, next to the parotid duct, there is often a accessory parotid gland,glandula parotis [ parotidea] accessoria. Vessels and nerves of the parotid gland. Arterial blood enters the branches of the parotid gland from the superficial temporal artery. Venous blood flows into the mandibular vein. The lymphatic vessels of the gland drain into the superficial and deep parotid lymph nodes. Innervation: sensitive - from the auriculotemporal nerve, parasympathetic - postganglionic fibers in the auriculotemporal nerve from the ear ganglion, sympathetic - from the plexus around the external carotid artery and its branches.