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.
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.
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.
Thu Feb 19, 2015 11:16 pm by tjp
Subject: ~Four Tiny Body Parts That Matter~