Blinking Big Mouth

By Peter Galvin, MD

Ever wonder why we have wisdom teeth? For most of us, they are nothing but trouble. If you join the U.S. Navy to work in submarines, you must have all four wisdom teeth removed before sailing. But wisdom teeth are just molars, like all the other grinders. For the first few years of life, we humans eat only soft foods that don’t require grinding. The first set of molars come in around age six, then another set appears at about age 12. The wisdom teeth are the final set of molars that appear at age 18 to 21. Our early ancestors were hunter gatherers who survived on leaves, roots, meat, and nuts, or foods that required a lot of grinding and crushing. They had bigger jaws than today’s humans, plus as humans evolved, we cooked our food which made it softer and required less grinding. But as our jaws shrunk, the number of teeth remained the same, necessitating the removal of the wisdom teeth in many people today to make more room in the jaw. I still have mine, so when someone tells me I have a big mouth, I guess they’re right. Who knows, maybe someday human evolution will get rid of those darned wisdom teeth.

Goosebumps, or goosepimples if you prefer (medically piloerection), are caused by contractions in the small muscles at the base of hair follicles. This creates a small depression, or dimple, on the skin’s surface, causing the hairs to stand upright. The name comes from the resemblance to the skin of a plucked bird. Our early ancestors not only had bigger jaws than us, but they were a lot hairier. All that hair provided insulation from the cold. While we don’t have enough body hair to insulate ourselves anymore (although I have seen some pretty hairy dudes), the muscle contractions and electrical stimulation that occurs during goosebumps helps to stimulate the body, which is why goosebumps from the cold go away when you warm up. Goosebumps are also associated with many emotional situations, from scary situations to rousing songs or high stakes sporting events. They are caused by the release of testosterone during high stress situations, which helps the fight-or-flight decision-making process. That’s when you feel your hair “prick up.” Next time you feel them, take a deep breath and relax, or maybe put on a sweater.

Finally, we blink automatically, on average 12 times a minute, 11,000 times a day, and 4.2 million times a year (remember to subtract for not blinking during sleep). That’s a lot of blinking blinks. Blinking lubricates the eyes and clears away any bacteria or dust that may have landed on your eye. When your eyes water, or tear, the extra fluid washes away dirt and debris, and your eyelid acts like a windshield wiper. We also blink in response to external stimuli, for example a sudden loud noise. Our eyes can close in 0.1 seconds after a stimulus is detected, like the bright bathroom light at 4 a.m., or a fistful of sand thrown at you. This is called the corneal reflex, a very deep-seated and primitive reflex, designed to protect your eyes from anything that may enter and harm them.

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