INTRODUCTION
Salivary glands release there secretions into ducts that leads to the mouth. There are three main pairs:
The parotid glands
The submandibular glands
The sublingual glands
The parotid glands:
These are situated one on each side of the face just below the external acoustic meatus. Each gland has a parotid duct opening in the mouth at the level of the second upper molar teeth.
The submandibular glands:
These lie on one on each side of the face under the angle of the jaw. The two submandibular ducts open on the floor of the mouth, one on each side of the frenulum of the tongue.
The sublingual glands:
These glands lie under the mucus membrane of the floor of the mouth in front of the submandibular glands. They have numerous small ducts that open into the floor of the mouth.
HISTOLOGY
The gland is internally divided into lobules. Blood vessels and nerves enter the glands at the hilum and gradually branch out into the lobules.
Acini
Secretory cells are found in a group, or acinus (plural, acini). Each acinus is located at the terminal part of the gland connected to the ductal system, with many acini within each lobule of the gland. Each acinus consists of a single layer of cuboidal epithelial cells surrounding a lumen, a central opening where the saliva is deposited after being produced by the secretory cells. The three forms of acini are classified in terms of the type of epithelial cell present and the secretory product being produced: serous, mucoserous and mucous.
Ducts
In the duct system, the lumina are formed by intercalated ducts, which in turn join to form striated ducts. These drain into ducts situated between the lobes of the gland (called interlobar ducts or secretory ducts). These are found on most major and minor glands (exception may be the sublingual gland
All of the human salivary glands terminate in the mouth, where the saliva proceeds to aid in digestion. The saliva that salivary glands release is quickly inactivated in the stomach by the acid that is present there but the saliva also contains enzymes that are actually activated by the acid.
