Parotid gland: pyramids, chipmunks, shark teeth
What is it? The largest of our salivary glands, which make saliva (aka spit). There is one on each side of our face, and they are shaped like an upside-down pyramid, sitting not far under the skin in front of and below our ear. What does spit do? Spit is a multi-tasker. It helps makes food moist, so we can chew and swallow it — anyone who has tried to eat dry crackers quickly will appreciate the value of wet food. Spit also helps us digest food, helps clean our mouth, and kills germs. Why the name? It’s named after its location: parotid is from the Greek words para , meaning beside, and otos , which means of the ear. How can it make you look like a chipmunk? Swelling of the gland, most commonly caused by the infectious disease mumps, distorts our face and is called ‘‘ chipmunk face’’. What’s it got to do with shark teeth? Spit reaches our mouth from the gland via a tube called Stensen’s duct. Niels Stensen, a 17th-century Danish anatomist, discovered it while dissecting animal heads — a favourite party piece of his. Stensen was also a geologist, and he was one of the first to realise that fossils came from living things. He’d dissected a shark’s head given to him by the Grand Duke of Tuscany, and saw that the teeth resembled strange objects found in rock called tongue stones. These were believed to be serpent tongues turned to stone by Saint Paul. Stensen correctly suggested they were originally shark’s teeth.