Facts about yourself & things you may not know

Things You Did not know About Yourself

    

The human body is truly a great machine, its sweaty, fluid-filled mechanism, constantly moving and mixing chemicals with precision and coordination, making everything from memories to mucus.

Here we explore some of the very complex and beautiful or just plain gross mysteries of how we function.

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.

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 likesneezing, laughing, crying and yawning may be ways of creating strong social bonds within a group.

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.

Cell Hairs Move Mucus

Most cells in our bodies sport hair-like organelles called cilia that help out with a variety of functions, from digestionto 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.

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 forreproduction. 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, apathyand poor decision-making skills as regions in the frontal cortex mature.

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.

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.

Bones Break (Down) to Balance Minerals

In addition to supporting the bag of organs and musclesthat 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 down�upping calcium levels in the body�until the appropriate extracellular concentration is reached.

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 ofCognition reports that episodes from your past are remembered faster and better while in a body position similar to the pose struck during the event.

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.

The top 10 Things that Make us Humans Special

Humans are unusual animals by any stretch of the imagination, ones that have changed the face of the world around us. What makes us so special when compared to the rest of the animal kingdom? Some things we take completely for granted might surprise you.

1

Speech

The larynx, or voice box, sits lower in the throat in humans than in chimps, one of several features that enable human speech. Human ancestors evolved a descended larynx roughly 350,000 years ago. We also possess a descended hyoid bone — this horseshoe-shaped bone below the tongue, unique in that it is not attached to any other bones in the body, allows us to articulate words when speaking.

2

Upright Posture

Humans are unique among the primates in how walking fully upright is our chief mode of locomotion. This frees our hands up for using tools. Unfortunately, the changes made in our pelvis for moving on two legs, in combination with babies with large brains, makes human childbirth unusually dangerous compared with the rest of the animal kingdom. A century ago, childbirth was a leading cause of death for women. The lumbar curve in the lower back, which helps us maintain our balance as we stand and walk, also leaves us vulnerable to lower back pain and strain.

3

Nakedness

We look naked compared to our hairier ape cousins. Surprisingly, however, a square inch of human skin on average possesses as much hair-producing follicles as other primates, or more — humans often just have thinner, shorter, lighter hairs.

4

Hands

Contrary to popular misconceptions, humans are not the only animals to possess opposable thumbs — most primates do. (Unlike the rest of the great apes, we don't have opposable big toes on our feet.) What makes humans unique is how we can bring our thumbs all the way across the hand to our ring and little fingers. We can also flex the ring and little fingers toward the base of our thumb. This gives humans a powerful grip and exceptional dexterity to hold and manipulate tools with.

5

Extraordinary Brains

Without a doubt, the human trait that sets us apart the most from the animal kingdom is our extraordinary brain. Humans don't have the largest brains in the world — those belong to sperm whales. We don't even have the largest brains relative to body size — many birds have brains that make up more than 8 percent of their body weight, compared to only 2.5 percent for humans. Yet the human brain, weighing only about 3 pounds when fully grown, give us the ability to reason and think on our feet beyond the capabilities of the rest of the animal kingdom, and provided the works of Mozart, Einstein and many other geniuses.

6

Clothing

Humans may be called "naked apes," but most of us wear clothing, a fact that makes us unique in the animal kingdom, save for the clothing we make for other animals. The development of clothing has even influenced the evolution of other species — the body louse, unlike all other kinds, clings to clothing, not hair

7

Fire

The human ability to control fire would have brought a semblance of day to night, helping our ancestors to see in an otherwise dark world and keep nocturnal predators at bay. The warmth of the flames also helped people stay warm in cold weather, enabling us to live in cooler areas. And of course it gave us cooking, which some researchers suggest influenced human evolution — cooked foods are easier to chew and digest, perhaps contributing to human reductions in tooth and gut size.

8

Blushing

Humans are the only species known to blush, a behavior Darwin called "the most peculiar and the most human of all expressions." It remains uncertain why people blush, involuntarily revealing our innermost emotions. The most common idea is that blushing helps keep people honest, benefiting the group as a whole.

9

Long Childhoods

Humans must remain in the care of their parents for much longer than other living primates. The question then becomes why, when it might make more evolutionary sense to grow as fast as possible to have more offspring. The explanation may be our large brains, which presumably require a long time to grow and learn.

10

Life after Children

Most animals reproduce until they die, but in humans, females can survive long after ceasing reproduction. This might be due to the social bonds seen in humans — in extended families, grandparents can help ensure the success of their families long after they themselves can have children.