Human Anatomy, Part 1 - K. A. Dyubenko, A. K. Kolomiysev, Yu. B. Chaykovsky 2002

Special Part
Splanchnology, splanchnologia [the study of viscera] — Digestive system, systema digestorium
Salivary glands

The oral glands, glandulae oris, are divided into Major and minor Salivary Glands, glandulae salivaria majores et minores (Fig. 201). The major salivary glands include:

- the parotid gland, glandula parotidea;

- the submandibular gland, glandula submandibularis;

- the sublingual gland, glandula sublingualis.

1. The parotid gland, glandula parotidea, is the largest of them (see Fig. 201). It is located in the parotid-masseteric region on the ramus of the Mandible, the masseter Muscle, and the retromandibular fossa. Triangular in shape, its upper border reaches the zygomatic arch and the external acoustic meatus; the posterior border extends to the mastoid process and the sternocleidomastoid muscle; and its lower border reaches the angle of the mandible. Externally, the parotid gland is covered by the parotid fascia, fascia parotidea.

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Fig. 201. Glands of the oral VESTIBULE AND ORAL cavity

The parotid gland consists of individual lobules that have excretory ducts which unite to form interlobular ducts; these, in turn, combine to form the main parotid duct, ductus parotideus.

The parotid duct runs superior to m. masseter and m. buccinator, parallel to the zygomatic arch and about 1 cm below it. The duct pierces the buccinator muscle and opens into the Oral Cavity opposite the upper second molar.

The Branches of the Facial Nerve pass through the parenchyma of the parotid gland, a clinical factor that must be considered in surgical practice, as they can be damaged during Procedures related to purulent parotitis, tumors, etc.

The Blood supply to the parotid gland is provided by branches of the External Carotid Artery: the superficial temporal, posterior auricular, and transverse facial Arteries. In addition, inconsistent sources such as the maxillary, deep auricular, and zygomatico-orbital arteries may contribute to the gland's blood supply. Venous drainage from the gland flows into the transverse facial vein, Veins OF THE masseter muscle, and the anterior and posterior auricular veins.

Lymphatic vessels drain into the parotid Lymph Nodes.

Sensory Innervation of the parotid gland is supplied by the parotid branches, rr. parotidei, and the auriculotemporal nerve, n. auriculotemporalis.

Parasympathetic innervation of the gland originates from the inferior salivatory Nucleus, n. salivatorius inferior, and the Glossopharyngeal nerve. Preganglionic fibers travel within this nerve and its branches (n. tympanicus, n. petrosus minor) to reach the otic ganglion, ganglion oticum. Postganglionic fibers reach the gland via branches of n. auriculotemporalis. Parasympathetic fibers stimulate secretion and dilate the Blood Vessels of the gland.

Sympathetic innervation of the gland is provided by preganglionic sympathetic fibers originating in the Gray matter of the upper thoracic segments of the Spinal Cord and synapsing in the superior cervical ganglion, ganglion cervicale superius. Postganglionic sympathetic fibers reach the parotid gland as part of the external carotid plexus, plexus caroticus externus. Sympathetic nerves constrict blood vessels and inhibit salivary secretion.

2. The submandibular gland, glandula submandibularis (see Fig. 201), is located in the submandibular triangle, is ovoid in shape, and consists of 10–12 lobules. Externally, it is surrounded by a capsule formed by the Superficial layer of the deep Cervical fascia. The excretory duct of the submandibular gland runs beneath the oral mucosa and opens onto the sublingual caruncle, caruncula sublingualis, alongside the duct of the sublingual gland.

The blood supply to the submandibular gland is derived from the facial, submental, and lingual arteries. Venous drainage is carried out by the corresponding veins.

Lymphatic vessels drain lymph from the gland into the submandibular lymph nodes.

Parasympathetic innervation of the gland is supplied by branches of the chorda tympani (n. intermedius) via the submandibular ganglion; sympathetic innervation is provided by the periarterial plexus of the external carotid artery.

3. The sublingual gland, glandula sublingualis (see Fig. 201), is situated beneath the Tongue on the mylohyoid muscle and is covered by a thin fascial capsule. The excretory duct of the gland opens onto the sublingual fold through 10–12 small orifices.

The blood supply to the gland is provided by branches of the lingual and facial arteries. Venous blood drains into the sublingual vein.

Lymphatic vessels drain lymph into the nearby submandibular lymph nodes.

Innervation is supplied by branches of the submandibular and sublingual ganglia, as well as sympathetic branches from the superior cervical ganglion.

The minor salivary glands, glandulae salivariae minores, of the oral cavity include the labial, buccal, lingual, palatine, and molar glands. They are located within the oral mucosa and open directly into the cavity through their ducts. Both major and minor glands secrete a fluid known as saliva, saliva, which moistens the oral mucosa and lubricates food during mastication. Saliva contains the enzyme amylase, which acts on dietary CARBOHYDRATES, converting starch into glucose. Thus, the digestive process begins right in the oral cavity.