The human body is a
great, sweaty, fluid-filled machine, moving and mixing chemicals with precision
and coordination, making everything from memories to mucus. Here we explore some
of the complex, beautiful or just plain gross mysteries of how you
function.
10. Your Stomach Secretes Corrosive
Acid
There's one dangerous liquid no airport security
can confiscate from you: It's in your gut. Your stomach cells secrete
hydrochloric acid, a corrosive compound used to treat metals in the industrial
world. It can pickle steel, but mucous lining the stomach wall keeps this
poisonous liquid safely in the digestive system, breaking down lunch. 09 more after the break...
09. Body Position Affects Your
Memory
Can't remember your anniversary, hubby? Try
getting down on one knee. Memories are highly embodied in our senses. A scent or
sound may evoke a distant episode from one's childhood. The connections can be
obvious (a bicycle bell makes you remember your old paper route) or inscrutable.
A recent study helps decipher some of this embodiment. An article in the January
2007 issue of Cognition reports that episodes from your past are remembered
faster and better while in a body position similar to the pose struck during the
event.
08. Bones Break (Down) to Balance
Minerals
In addition to supporting the bag of organs and
muscles that is our body, bones help regulate our calcium levels. Bones contain
both phosphorus and calcium, the latter of which is needed by muscles and
nerves. If the element is in short supply, certain hormones will cause bones to
break downeupping calcium levels in the bodyeuntil the appropriate extracellular
concentration is reached.
07. Much of a Meal is Food For
Thought
Though it makes up only 2 percent of our total
body weight, the brain demands 20 percent of the body's oxygen and calories. To
keep our noggin well-stocked with resources, three major cerebral arteries are
constantly pumping in oxygen. A blockage or break in one of them starves brain
cells of the energy they require to function, impairing the functions controlled
by that region. This is a stroke.
06. Thousands of Eggs Unused by
Ovaries
When a woman reaches her late 40s or early 50s,
the monthly menstrual cycle that controls her hormone levels and readies ova for
insemination ceases. Her ovaries have been producing less and less estrogen,
inciting physical and emotional changes across her body. Her underdeveloped egg
follicles begin to fail to release ova as regularly as before. The average
adolescent girl has 34,000 underdeveloped egg follicles, although only 350 or so
mature during her life (at the rate of about one per month). The unused egg
follicles then deteriorate. With no potential pregnancy on the horizon, the
brain can stop managing the release of ova.
05. Puberty Reshapes Brain Structure,
Makes for Missed Curfews
We know that hormone-fueled changes in the body
are necessary to encourage growth and ready the body for reproduction. But why
is adolescence so emotionally unpleasant? Hormones like testosterone actually
influence the development of neurons in the brain, and the changes made to brain
structure have many behavioral consequences. Expect emotional awkwardness,
apathy and poor decision-making skills as regions in the frontal cortex
mature.
04. Cell Hairs Move Mucus
Most cells in our bodies sport hair-like
organelles called cilia that help out with a variety of functions, from
digestion to hearing. In the nose, cilia help to drain mucus from the nasal
cavity down to the throat. Cold weather slows down the draining process, causing
a mucus backup that can leave you with snotty sleeves. Swollen nasal membranes
or condensation can also cause a stuffed schnozzle.
03. Big Brains Cause Cramped
Mouths
Evolution isn't perfect. If it were, we might
have wings instead of wisdom teeth. Sometimes useless features stick around in a
species simply because they're not doing much harm. But wisdom teeth weren't
always a cash crop for oral surgeons. Long ago, they served as a useful third
set of meat-mashing molars. But as our brains grew our jawbone structure
changed, leaving us with expensively overcrowded mouths.
02. The
World Laughs with You
Just as watching someone yawn can induce the
behavior in yourself, recent evidence suggests that laughter is a social cue for
mimicry. Hearing a laugh actually stimulates the brain region associated with
facial movements. Mimicry plays an important role in social interaction. Cues
like sneezing, laughing, crying and yawning may be ways of creating strong
social bonds within a group.
01.
Your Skin Has Four Colors
All skin, without coloring, would appear creamy
white. Near-surface blood vessels add a blush of red. A yellow pigment also
tints the canvas. Lastly, sepia-toned melanin, created in response to
ultraviolet rays, appears black in large amounts. These four hues mix in
different proportions to create the skin colors of all the peoples of
Earth.
Via
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