126. Salivary glands. Classification, position, structure. Blood and nerve supply.

SALIVARY GLANDS

• Salivary glands secrete saliva into oral cavity
• Saliva:
• Clear, tasteless & odorless fluid
• keeps mouth's mucosa hydrated
• Lubricate food
• Makes swallowing easier.
• Starts digestion of strach.
• bec. it contains amylase enzyme

Parotid gland: (pair)

• The largest of the three paired salivary glands
• Triangular in shape.

Position:

• Anterior and below the lower half of the ear

Coverings:

• False Capsule: formed by the investing layer of deep cervical fascia
• True capsule: Condensation of the fibrous stroma of the gland

It has 3 surfaces & 3 bordars:

Structures within the parotid gland:

1. External Carotid artery (the deepest structure)
2. Retromandibular vein (it is formed within the gland by union of maxillary and superficial temporal vein).
3. Facial nerve (most superficial structure) (runs horizontally)

• It enters the gland and divide within its substance giving 5 terminal branches).

Submandibular gland:

• Located within the submandibular triangle of the neck,

Structure:

Each submandibular gland has:

1. Superficial loob
2. Deep loob

seperated by the mylohyoid muscle.

• Each gland has submandibular duct or Wharton's duct:
• Starts from anterior end of deep part of the gland.
• 2 inches long.
• excretes the contents of the gland onto the floor of the oral cavity.
• It runs on hyoglossus muscle, situated btw 2 nerves (lingual & hypoglossal)
• Then runs btw. sublingual gland and genioglossus muscle.
• It opens on the summit of sublingual papilla.

Blood Supply of submandibular glands:

1. Facial & lingual arteries
2. Facial & lingual veins.

Sublingual gland:

• Have almond-shaped.
• Lie on the floor of the oral cavity.
• They are situated underneath the tongue, bordered laterally by the mandible and medially by genioglossus muscle.

Both sublingual glands unite anteriorly and form a single mass through a horseshoe configuration around the lingual frenulum. The superior aspect of this U-shape forms an elevated, elongate crest of mucous membrane called the sublingual fold (plica sublingualis). Each sublingual fold extends from a posterolateral position and traverses anteriorly to join the sublingual papillae at the midline, either side of the lingual frenulum.

Blood Supply:

Blood supply is via the sublingual and submental arteries which arise from the lingual and facial arteries respectively; both of the external carotid artery.

Venous drainage is through the sublingual and submental veins which drain into the lingual and facial veins respectively; both then draining into the internal jugular vein.

+ Blood Supply of parotid gland:

By the posterior auricular & superficial temporal arteries