The salivary gland is made up of many small units, or lobules, all enclosed within a capsule. The primary function of the salivary gland is to create saliva. It helps to think of the salivary gland as a large interconnected network, analogous to a tree. The production of saliva occurs in the lobules (think of these lobules as the individual leaves of the tree). Saliva then drains into many branching ducts, which carry the saliva to even larger ducts. These ducts eventually coalesce into one large duct (similar to the tree trunk) that empties into the mouth. This production and transport of saliva into the mouth is essential, as it helps to lubricate food and make it easier to swallow. Additionally, saliva contains enzymes which perform a variety of functions. One enzyme, known as amylase, helps to begin the breakdown of starches in the mouth. Another group of enzymes, known as lysozymes, destroy bacteria and other pathogens, preventing them from entering the body any further.
In the human body, there are three types of salivary glands: submandibular, sublingual, and parotid. The names describe the locations in which these glands can be found. The submandibular glands are found beneath the lower jaw. The sublingual glands are underneath your tongue, and the smallest of the salivary glands. The largest salivary glands, known as the parotid glands, are located on the sides of the face, just slightly above the jawline.
As with any other part of the body, the salivary glands are susceptible to disease and dysfunction. The most common infection within the salivary glands is mumps, which specifically affects the parotid glands. Due to this viral infection, the parotid glands can swell and become extraordinarily painful. This infection is most commonly found in children, although immunizations have decreased its incidence drastically. Also, ducts within the salivary glands can become blocked, usually by a stone called a “sialolith.” As saliva cannot get past this stone, the salivary glands may swell to a substantial size and cause severe pain. Salivary glands that are blocked in such a manner can become infected, and it is necessary to remove the stone either through surgical means or by lithotripsy, which employs shock waves to break up the stone into smaller pieces. Cancer can also occur in the salivary glands. Although there is no way of preventing some of these diseases, it has been noted that dehydration can cause or exacerbate salivary gland problems, so make sure to stay well hydrated to promote optimal salivary gland health.