What keeps our mouths from becoming dry? Saliva, of course. Besides keeping our mouths moist, saliva has many other important functions in digestion, immunity and protection of teeth. Saliva is produced by organs called the salivary glands. Learn how many salivary glands the body has, where they are located and how they produce saliva and deliver it to the oral cavity.
There are three pairs of major salivary glands:
- parotid gland
- submandibular gland
- sublingual salivary gland
Apart from these, there are many minor salivary glands, really tiny glands located all over the oral cavity, pharynx and sometimes, even the nose.
Parotid Gland – Largest Salivary Gland
There are actually two parotid glands, one on each side. This gland occupies the area just in front of and below the ear. It has a superficial and a deep part with branches of the facial nerve, the nerve for the facial muscles, running in between. Inside its thick capsule, there are numerous ‘acini’, groups of cells that do the job of producing the saliva.
Saliva synthesized by this gland is transported to the mouth via a tube called the Stensen’s duct. This duct opens into the oral cavity opposite the second molar of the upper jaw. The parotid duct passes through the buccal fat in the cheek and the buccinator muscle before it opens into the mouth. When we blow, the buccinator muscle contracts around the tube, preventing air from entering it.
Do you want to see where it opens into the mouth? Stand in front of the mirror, open your mouth and use a finger to pull your cheek back. Now look at the teeth of the upper jaw on that side and identify the second of the molars, the large square teeth located along the sides. You can see a small, raised, red spot on the buccal mucosa, the inside of the cheek, just opposite this tooth. This is the opening of the parotid duct.
This gland swells up in case of an infection or parotitis. Mumps is one of the causes for it to swell up. Parotid swellings can be very painful and sometimes even lead to abscess formation.
Submandibular Salivary Gland
There are two submandibular glands, one on each side, located under the mandible or the lower jaw bone, just behind the chin. These glands are smaller than the parotid glands. Inside the capsule, the structure is similar to the parotid gland. Saliva produced by these glands is transported to the mouth by the submandibular duct or the Wharton’s duct. The opening of this tube can be readily spotted under the tongue. Just below the tongue is a fold of tissue with two raised hillocks on either side. You can see the duct opening at the tip of this hillock.
This gland is more prone to stone formation than the parotid gland. Stones sometimes form within its duct and may be seen as a swelling in the floor of the mouth under the tongue.
Sublingual Salivary Glands
These are two small glands located in the floor of the mouth, the part of the oral cavity under the tongue. Saliva from these glands reaches the mouth via many small openings in the floor of the mouth. Rarely, one of these glands may become clogged and give rise to a condition called a rannula where there is a large swelling under the tongue.
Saliva from the parotid gland is usually watery, while that from the submandibular gland is thicker, containing more mucous. Diseases of the salivary glands can result in decreased production of saliva causing a dry mouth.
Sources
Romanes, G.J. “Cunningham’s Manual of Practical Anatomy” (Oxord University Press; 15th Edition, 2003)
Lakshmi Ananth - Lakshmi Ananth is a practising ENT, head and neck surgeon and has faculty position at a medical college. She is specially interested in ...
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