Topography and characteristics of major salivary glands
Humans have three pairs of major salivary glands, each with its own anatomical and physiological features:
- Parotid gland (gl. parotis). It is the largest one. It produces a serous type of secretion. Its excretory duct opens into the oral cavity: the orifice is located on a special papilla at the level of the maxillary molars.
- Submandibular gland (gl. submandibularis, or gl. submaxillaris). Located within the boundaries of the submandibular triangle. Produces a mixed (seromucous) secretion. The duct of the gland opens at the apex of the sublingual caruncle, which is located in the region of the lingual frenulum.
- Sublingual gland (gl. sublingvalis). Located in the sublingual region, occupying the space between the inner surface of the mandible and the lateral wall of the tongue. Mixed type secretion. The orifice of the excretory duct opens in the same place as the submandibular one — at the level of the corresponding papilla.
Minor Salivary Glands
In addition to the large paired organs, numerous minor salivary glands are scattered in the submucosal layer of the oral cavity. They are usually classified by their location:
- Labial;
- Buccal;
- Lingual;
- Palatine;
- Molar.
The physiological role of this group is extremely important: it is the minor glands that provide up to 31% of the total daily saliva secretion volume, maintaining constant moisturization of the mucous membrane.
Functions of salivary glands and composition of secretion
The glands perform four main functions: secretory, recretory, excretory, and incretory.
Participation in digestion. Saliva moistens food and forms the food bolus. Due to its rich enzymatic composition (amylase, lipase, hyaluronidase, esterase, DNase, RNase), the breakdown of proteins, fats, carbohydrates, and nucleic acids begins already in the oral cavity.
Protective and trophic effect. The secretion mechanically washes away food debris and creates a reliable barrier of mucin and immunoglobulins (type A antibodies). Saliva maintains optimal pH, protects tooth enamel, provides local cellular and humoral immunity, and its enzymatic systems are capable of destroying viruses.
Incretory function. Salivary glands synthesize a number of hormones and hormone-like substances released into the blood. Among them, the most clinically significant are:
- Parotin;
- Nerve growth factor;
- Epidermal growth factor;
- Insulin-like protein.
Approaches to the classification of salivary gland diseases
According to the International Classification of Diseases (ICD-10), salivary gland pathologies are classified under block K11. This includes conditions such as sialadenitis, abscesses, fistulas, sialolithiasis (duct stones), mucocele (including ranula), and secretory disorders (xerostomia, ptyalism).
However, in the clinical practice of dentists in the Russian Federation, ICD-10 is practically not used. This is due to its insufficient adaptation: for example, hypertrophy, atrophy, and secretory disorders in ICD-10 are considered not as independent nosologies, but merely as symptoms of other diseases. In addition, such important conditions as Sjögren's syndrome, Heerfordt's syndrome, and Küttner's tumor are excluded from this category (patients with these diagnoses are still subject to follow-up dispensary observation and treatment by a maxillofacial surgeon).
Russian classification (by I.F. Romacheva and V.V. Afanasyev) Due to the aforementioned shortcomings, a more practical classification is used in Russia, dividing pathologies into three major groups:
- Developmental defects: dystopia, aplasia, duct defects (stenosis, ectasia).
- Injuries: fistulas, strictures, duct obliteration, traumatic cysts.
- Sialadenoses: reactive-dystrophic lesions occurring against the background of endocrine (diabetes mellitus, thyroid pathologies) or psychosomatic diseases.
Briefly: answers to topical questions
What is the blood and lymphatic supply of the parotid salivary gland?
Blood supply to the parotid salivary gland is provided by branches of the external carotid artery, including the superficial temporal artery. The external carotid artery and its branches also pass through the parotid region. Venous drainage is connected to the retromandibular vein. There are lymph nodes in the parotid-masseteric region.
Which types of nerves provide secretory innervation to the submandibular and sublingual salivary glands?
Secretory innervation of the submandibular and sublingual salivary glands is provided by efferent parasympathetic and sympathetic nerve fibers.
- Parasympathetic nerves (chorda tympani) — chorda tympani fibers from the facial nerve synapse in the submandibular (ganglion submandibulare) and sublingual (g. s/linguale) ganglia. Secretory fibers from the otic ganglion (ganglion oticum) also supply the sublingual gland.
- Sympathetic nerves (nervi sympathici) — fibers from the superior cervical ganglion accompany the facial artery (a. facialis) to the submandibular gland and the superficial temporal artery (a. temporalis superficialis) to the sublingual gland.
What is the histological structure and types of terminal portions (acini) of the salivary glands?
The terminal portions of the salivary glands are divided into three types depending on the secretion produced:
- Protein (serous) portions contain serocytes and produce a protein secretion.
- Mucous portions contain mucocytes, have a light appearance; mucocyte nuclei are flattened and pushed toward the basement membrane. They produce a mucous secretion.
- Mixed portions contain serocytes and mucocytes and produce a protein-mucous secretion. They consist of a central mucous part and a peripheral protein component — the serous demilune of Gianuzzi.
In the parotid gland, the terminal portions consist of serocytes and are surrounded externally by myoepithelial cells.
The functions of the salivary glands are easy to remember by the acronym SIRE: Secretory, Incretory, Recretory, Excretory.
Class and exam questions
Where does the excretory duct of the parotid salivary gland open?
The orifice of the parotid duct opens into the vestibule of the oral cavity on a specific papilla located at the level of the upper molars.
What is the incretory function of the salivary glands?
It consists in the synthesis of hormones and biologically active substances, such as parotin, nerve growth factor, epidermal growth factor, and insulin-like protein.
Why is ICD-10 rarely used in the Russian Federation for diagnosing salivary gland diseases?
ICD-10 is poorly adapted to the clinical practice of dentists: many independent diseases are listed in it only as symptoms, and a number of specific syndromes (Sjögren's, Küttner's) are entirely excluded from this section.
What else to study on this topic
- Sialolithiasis: causes of stone formation in the ducts
- Salivary gland cysts: distinction between ranula and mucocele
- Sialadenoses associated with diabetes mellitus and thyroid dysfunction
- Traumatic injuries: fistulas and strictures of excretory ducts
- Congenital malformations: dystopia and aplasia of the glands
Master the entire topic in the course "Surgical Dentistry"
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Anatomy and Physiology of the Salivary Glands" and 866 more pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 28 video lessons on the subject
Other topics in the section "Chapter 10. Diseases and injuries of the salivary glands (V.V. Afanasiev)"
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.