#Health & Fitness
Small Wonders: Four Tiny Body Parts That Matter
by Allison Ford
These body parts may serve curious purposes, but we need them all the same.
It’s sometimes hard to know which parts of the human body serve a purpose and which parts don’t. Sometimes it’s obvious—feet and fingers are important, while evolutionary remnants like the appendix aren’t. Thumbs are an absolute necessity, while we could quite easily live without earlobes.
The purpose of some parts of the body, though, is a little less clear. Are they really contributing to our overall health and welfare, or are they just another bothersome area to scrub in the shower? These four body parts may seem trivial, but without them, things just wouldn’t be the same.
High Brows and Low Brows
If the eyes are the window to the soul, then the eyebrows are the curtains that frame and protect them. Eyebrows are one of our most expressive facial features—furrowed or uplifted brows leave no doubt about what we’re feeling. It’s not just their tiny swatches of hair that make eyebrows special; it’s also their shape in relation to the eye socket. Because of their arched shape, water (from rain, sweat, or other moisture) is diverted to the sides of our faces, keeping eyes dry and free from salt, debris, and other irritants.
Even though our brows are important for keeping moisture on our faces at bay, most researchers agree that we could get by without eyebrows—and plenty of people do, from alopecia sufferers to victims of overzealous tweezers. Some doctors think that if we didn’t have eyebrows at all, humans would have developed another way—very thick eyelashes, for example, or a more prominent ridge in the skull—to achieve the same purpose.
Prints Make for Sticky Fingers
They make it easier for the police to identify who committed a crime, but fingerprints also serve a vital purpose for law-abiding citizens. Scientists have long theorized that besides being a completely unique way to identify people, the ridges on our fingers are what help humans pick up and grip objects more securely. All primates have fingerprints, as do some tree-dwelling mammals, such as koalas. Some researchers think that fingerprints also help keep our fingertips dry by channeling moisture away, allowing us to maintain a grip even if our hands are wet.
Living without fingerprints would be very difficult, especially for people who work with their hands. People whose fingerprints have worn off because of burns or overuse often find that the smooth calluses that develop on the fingertips make it nearly impossible to maintain a grip on anything.
Tough as Fingernails
Our nails aren’t just a convenient place to put colored polish. Nails, on both the fingers and the toes, are made of keratin, the same stuff our hair contains, only denser and harder. Nails are the primate equivalent of hooves and claws on other animals. Animals use their claws or talons to catch prey, climb trees, and defend themselves. Humans have evolved to the point where fingernails are not vital for survival, but there’s no doubt that they’re useful. They help when we’re performing fine motor skills, like untying knots and preparing food. They’re also important for scratching (a pleasurable experience most mammals enjoy) and grooming.
Toenails are less important than fingernails. At this stage of our evolution, they’re little more than remnants. Watching apes and monkeys use their feet to grasp objects reminds us that at one point it was useful to have nails on our toes, but they’re simply not as necessary now. Apes and monkeys also have opposable thumbs on their feet that help their dexterity. Since humans don’t have these, our feet are useful mainly for ambulation.
One thing that nails are not for is protection of the nail bed. Contrary to popular belief, they serve no protective purpose, and without fingernails or toenails, our digits would not be uncomfortably sensitive; the nail bed would simply become harder and tougher to accommodate the new level of exposure.
The Eyelashes Grab It
We may think of long, lush eyelashes as signs only of fertility and attractiveness, but they are important for eye health, too. Lashes trap debris and dirt, preventing it from coming in contact with our eyes, which could cause injuries. Eyelashes’ roots also have connections to nerve endings, and a foreign object brushing up against the lashes can trigger a neurological reflex to close the eye, keeping it protected.
Even though eyelashes serve an important purpose, however, people can live without them. The size and thickness of lashes vary widely among people, and those with certain forms of alopecia or who are undergoing chemotherapy often have no lashes at all. Although these people don’t suffer from any seriously debilitating effects, they do have to work a little harder to protect their eyes from irritants. For most people, the lack of eyelashes is more a cosmetic concern than a medical one, and many resort to false lashes or lash-enhancing medications and procedures.
Over millions of years, the human body has adapted to maximize efficiency, protect our most delicate areas, and be durable and tough. Although these body parts may seem like mere afterthoughts, they actually provide an important service. Living without them might be possible, but it’s definitely better to have them than to go without.
Updated November 9, 2010