Saliva has more functions than you might realize. (iStockphoto/The Washington Post)

When kids think about saliva, it’s often in the context of how far they can spit or the way saliva changes color if they’ve been eating something like Skittles. And while I agree that the aerodynamics of spit is fun to watch, saliva has a loftier goal than being launched through the air in search of a target.

Your body is loaded with glands. Some produce tears. Some produce sweat. Some produce oil. Your mouth is home to six large and more than 750 small glands that make saliva. The large salivary glands come in pairs:

●Parotid glands are located inside your cheeks near the ear.

●Submandibular glands are located on the floor of your mouth by the lower jaw.

●Sublingual glands are located under the front of your tongue.

The small salivary glands are one or two millimeters in size. They can be found within the “mucosa” of your cheeks, lips, soft palate, hard palate, the floor of your mouth and even your throat. Mucosa is the scientific name for the moist tissue that lines the inside areas of your body: mouth, throat, nasal passages, etc.

Saliva is 99 percent water. The rest is composed of mucus, salts, enzymes, protein and antibodies (chemicals that help your body fight infection). A small amount of saliva is continually secreted into your mouth, but 90 percent of it is released in response to eating or drinking. The average adult makes about a quart of saliva daily.

Saliva has many jobs:

●It keeps your oral mucosa moist.

●It helps prevent cavities. (But you still need to brush your teeth!)

●It mixes with food, making it easier to swallow.

●By liquefying food, saliva makes it easier to taste what you’re eating.

●The parotid gland makes amylase (pronounced AM-uh-lace), an enzyme that begins digesting starch in your mouth.

Before a vaccine was developed in the 1960s, thousands of American children came down with the mumps every year. The mumps virus mainly attacks the parotid gland. Kids who get the mumps develop a low-grade fever, muscle aches, fatigue and very swollen parotid glands. Imagine a hamster whose cheeks are bulging with food, and you’ll have a picture of what kids look like with the mumps. Nowadays, getting the mumps is rare, but other viruses can occasionally infect the parotid glands. As a pediatrician, I see a case of parotitis, or inflammation of the parotid gland, about once a year.

Here are some other cool facts about saliva:

●You produce less saliva while you sleep. That’s why your mouth is dry when you wake up.

●The venom glands of poisonous snakes and Gila monsters are modified salivary glands.

●Two bird species in the swiftlet family build their nests completely from saliva. Bird’s nest soup, which is made from these nests, is a delicacy in China. The empty nests are harvested from the walls of high caves. They are then cleaned and cooked in broth. I hear that it’s an acquired taste.

Bennett is a Washington pediatrician. The second edition of his book “Waking Up Dry: A Guide to Help Children Overcome Bedwetting” was published last May.

Saliva and swallowing pills

Whenever I think about saliva, I remember how hard it is for some people to swallow pills. This usually comes from a fear that the pill will get stuck in their throat.

Fortunately, there’s a way around this problem. You swallow pieces of meat or chicken every day that are much bigger than pills. The reason food doesn’t get stuck can be explained with one word: saliva. When you chew, saliva gets mixed in with the food. This makes what you’ve eaten gooey and soft. So when food reaches your throat, rather than getting stuck, it changes shape and slides right down.

The way to swallow a pill is to hide it in something you’ve partially chewed. The best food to use is bread because it’s very sticky when chewed. (This allows it to completely enclose the pill.) Start with something small, such as a Tic Tac. Once you’ve mastered Tic Tacs, work your way up to something the size of a Mike and Ike. Once you can do that, you’ll be able to swallow any pill a doctor prescribes.