Chapter 15. The Salivary Glands

A. Introduction

Page 1

Image source: Mayo Foundation for Medical Education and Research


Mammals have three pairs of major salivary glands: the parotid glands, the submandibular (submaxillary) glands, and the sublingual glands. These glands are compound tubuloalveolar exocrine glands that secrete the serous and mucous components of saliva into the oral cavity.

The salivary glands produce about 1250 ml of saliva per day. Saliva is a mixture of the secretions from the serous acini, mucus acini and mixed acini of the salivary glands, the composition of which is modified by the glands' duct system. Saliva is 98% water and contains a variety of electrolytes, mucus glycoproteins, a variety of other proteins, such as salivary amylase, lysozyme, lactoferrin and secretory immunoglobulin A, urea and other substances.

Saliva has a long list of important physiological functions. These include

  • moistening and lubricating the oral mucosa
  • moistening and dissolves foods for swallowing and taste
  • digestion of starch
  • controlling he bacterial content of the oral cavity

The Parotid Glands

The parotid glands are the largest of the major salivary glands.  They are responsible for secreting approximately 30% of the total salivary output of the salivary glands.  The parotid glands are located anterior to the ear, just inferior to the zygomatic arch. They are completely serous glands.  Their serous secretion enters the oral cavity via Stensen's duct.

The Submandibular Glands

The submandibular glands are located beneath the floor of the mouth, along the interior surfaces of the mandible. They are responsible for secreting approximately 65% of the total salivary output of the salivary glands.  They are mixed glands, i.e., made up of serous and mixed mucus acini, but are predominantly serous. The secretion enters the oral cavity via Wharton's ducts.

The Sublingual Glands

The sublingual glands are the smallest of the major salivary glands and secrete approximately 5% of the total salivary output of the salivary glands.  The sublingual glands are located directly beneath the floor of the mouth, just anterior to the submandibular glands.  They are categorized as mixed salivary glands.  However, their acini are nearly all mucus acini, some are mixed, very few are serous.