Anatomy and Physiology: Six Facts about the Salivary Glands and Saliva

Ever been so angry you could spit? If you're angry right now, please don't spit—it was just an expression.

As gross as spit is, it's also incredibly interesting. Your body puts a lot into making your saliva, regardless of what you're using it for (eating, keeping your throat dry, drooling into your pillow, etc.). What about it is so interesting, you ask? Read on, dear reader, and find out!

1. You have six salivary glands.

Not one, not two, but six glands in your head that produce nearly two liters of saliva every day. Your sublingual, submaxillary, and parotid glands work together to keep your mouth and throat from turning to dust. No, seriously, have you ever seen a dried-out mucous membrane? It's like watching The Mummy all over again.

Image captured from Human Anatomy Atlas.

2. Saliva is 99% water.

Actually, saliva is around 99.5% water, which is why it's so important for you to stay hydrated. In addition to water, enzymes and "buffers" (things that maintain a balanced pH level) help keep the status quo in the oral cavity.

3. Without saliva, you couldn't taste.

If you've ever had a case of dry mouth, you'd have noticed that you weren't able to taste things very well. A dry tongue actually can't taste a thing! Chemicals in food need to dissolve in saliva for the taste buds in your tongue to detect them, and saliva constantly keeps the receptors nice and wet.  

4. Saliva acts as a warning before you vomit.

Talk about your gross headers, but there you have it. Ever notice that your mouth fills with saliva before you're about to vom? It happens because your body is trying to digest whatever is ailing it, and since digestion begins in the mouth your salivation mechanism is revved up. 

5. Sometimes the sublingual glands turn you into a human fountain.

Image captured from Human Anatomy Atlas.

Don't even ask. But sometimes if you yawn, you'll briefly become a human fountain when a small stream of saliva erupts from under your tongue. This is due to the contraction of a muscle that pushes against the sublingual glands, which sends the saliva shooting out—sometimes at great distances!

6. Saliva has healing properties—so long as the thing being healed is in your mouth.

When a dog gets hurt, what's the first thing it does? It licks its wound. To some degree, the same thing happens with humans. Ever notice that a wound in your mouth heals exponentially faster than a wound anywhere else in the body and never leaves behind a scar? This is because your saliva contains immune cells, antimicrobial and antifungal proteins, and growth factors that promote wound healing.

However, that only goes for wounds in the mouth. In addition to all those healing factors, your saliva is also chock-full of bacteria, which could infect a wound on your skin.