Facts About the Human Body
The human body is an incredibly complex
and intricate system, one that still baffles doctors and researchers on a
regular basis despite thousands of years of medical knowledge. As a result, it
shouldn’t be any surprise that even body parts and functions we deal with every
day have bizarre or unexpected facts and explanations behind them. From sneezes
to fingernail growth, here are 100 weird, wacky, and interesting facts about
the human body.
The Brain
The human brain is the most complex and
least understood part of the human anatomy. There may be a lot we don’t know,
but here are a few interesting facts that we’ve got covered.
1. Nerve impulses
to and from the brain travel as fast as 170 miles per hour: Ever wonder how you can react so fast to things around you
or why that stubbed toe hurts right away? It’s due to the super-speedy movement
of nerve impulses from your brain to the rest of your body and vice versa,
bringing reactions at the speed of a high powered luxury sports car.
2. The brain
operates on the same amount of power as 10-watt light bulb: The cartoon image of a light bulb over your head when a
great thought occurs isn’t too far off the mark. Your brain generates as much
energy as a small light bulb even when you’re sleeping.
3. The human brain
cell can hold 5 times as much information as the Encyclopedia Britannica. Or any other encyclopedia for that matter. Scientists have
yet to settle on a definitive amount, but the storage capacity of the brain in electronic terms
is thought to be between 3 or even 1,000 terabytes. The National Archives of
Britain, containing over 900 years of history, only takes up 70 terabytes,
making your brain’s memory power pretty darn impressive.
4. Your brain uses
20% of the oxygen that enters your bloodstream: The brain only makes up about 2% of our body mass, yet
consumes more oxygen than any other organ in the body, making it extremely
susceptible to damage related to oxygen deprivation. So breathe deep to keep
your brain happy and swimming in oxygenated cells.
5. The brain is
much more active at night than during the day: Logically, you would think that all the moving around,
complicated calculations and tasks and general interaction we do on a daily
basis during our working hours would take a lot more brain power than, say,
lying in bed. Turns out, the opposite is true. When you turn off your brain
turns on. Scientists don’t yet know why this is but you can thank the hard work
of your brain while you sleep for all those pleasant dreams.
6. Scientists say
the higher your I.Q: the more you dream: While
this may be true, don’t take it as a sign you’re mentally lacking if you can’t
recall your dreams. Most of us don’t remember many of our dreams and the
average length of most dreams is only 2-3 seconds–barely long enough to
register.
7. Neurons continue
to grow throughout human life: For years
scientists and doctors thought that brain and neural tissue couldn’t grow or
regenerate. While it doesn’t act in the same manner as tissues in many other
parts of the body, neurons can and do grow throughout your life, adding a whole
new dimension to the study of the brain and the illnesses that affect it.
8. Information
travels at different speeds within different types of neurons: Not all neurons are the same. There are a few different
types within the body and transmission along these different kinds can be as
slow as 0.5 meters/sec or as fast as 120 meters/sec.
9. The brain itself
cannot feel pain: While the brain might be
the pain center when you cut your finger or burn yourself, the brain itself
does not have pain receptors and cannot feel pain. That doesn’t mean your head
can’t hurt. The brain is surrounded by loads of tissues, nerves and blood
vessels that are plenty receptive to pain and can give you a pounding headache.
10. 80% of the brain
is water: Your brain isn’t the firm, gray
mass you’ve seen on TV. Living brain tissue is a squishy, pink and jelly-like
organ thanks to the loads of blood and high water content of the tissue. So the
next time you’re feeling dehydrated get a drink to keep your brain hydrated.
Hair and Nails
While they’re not a living part of your
body, most people spend a good amount of time caring for their hair and nails.
The next time you’re heading in for a haircut or manicure, think of these
facts.
11. Facial hair grows
faster than any other hair on the body: If
you’ve ever had a covering of stubble on your face as you’re clocking out at 5
o’clock you’re probably pretty familiar with this. In fact, if the average man
never shaved his beard it would grow to over 30 feet during his lifetime, longer
than a killer whale.
12. Every day the
average person loses 60-100 strands of hair: Unless you’re already bald, chances are good that you’re shedding pretty
heavily on a daily basis. Your hair loss will vary in accordance with the
season, pregnancy, illness, diet and age.
13. Women’s hair is
about half the diameter of men’s hair: While
it might sound strange, it shouldn’t come as too much of a surprise that men’s
hair should be coarser than that of women. Hair diameter also varies on average
between races, making hair plugs on some men look especially obvious.
14. One human hair
can support 3.5 ounces: That’s about the
weight of two full size candy bars, and with hundreds of thousands of hairs on
the human head, makes the tale of Rapunzel much more plausible.
15. The fastest
growing nail is on the middle finger: And
the nail on the middle finger of your dominant hand will grow the fastest of
all. Why is not entirely known, but nail growth is related to the length of the
finger, with the longest fingers growing nails the fastest and shortest the
slowest.
16. There are as many
hairs per square inch on your body as a chimpanzee: Humans are not quite the naked apes that we’re made out to
be. We have lots of hair, but on most of us it’s not obvious as a majority of
the hairs are too fine or light to be seen.
17. Blondes have more
hair. They’re said to have more fun, and
they definitely have more hair. Hair color determines how dense the hair on
your head is. The average human has 100,000 hair follicles, each of which is
capable of producing 20 individual hairs during a person’s lifetime. Blondes
average 146,000 follicles while people with black hair tend to have about
110,000 follicles. Those with brown hair fit the average with 100,000 follicles
and redheads have the least dense hair, with about 86,000 follicles.
18. Fingernails grow
nearly 4 times faster than toenails. If
you notice that you’re trimming your fingernails much more frequently than your
toenails you’re not just imagining it. The nails that get the most exposure and
are used most frequently grow the fastest. On average, nails on both the toes
and fingers grow about one-tenth of an inch each month.
19. The lifespan of a
human hair is 3 to 7 years on average: While
you quite a few hairs each day, your hairs actually have a pretty long life
providing they aren’t subject to any trauma. Your hairs will likely get to see
several different haircuts, styles, and even possibly decades before they fall
out on their own.
20. You must lose
over 50% of your scalp hairs before it is apparent to anyone: You lose hundreds of hairs a day but you’ll have to lose a
lot more before you or anyone else will notice. Half of the hairs on your
pretty little head will have to disappear before your impending baldness will
become obvious to all those around you.
21. Human hair is
virtually indestructible. Aside from it’s
flammability, human hair decays at such a slow rate that it is practically
non-disintegrative. If you’ve ever wondered how your how clogs up your pipes so
quick consider this: hair cannot be destroyed by cold, change of climate,
water, or other natural forces and it is resistant to many kinds of acids and
corrosive chemicals.
Internal Organs
Though we may not give them much
thought unless they’re bothering us, our internal organs are what allow us to
go on eating, breathing and walking around. Here are some things to consider
the next time you hear your stomach growl.
22. The largest
internal organ is the small intestine.
Despite being called the smaller of the two intestines, your small intestine is
actually four times as long as the average adult is tall. If it weren’t looped
back and forth upon itself it wouldn’t fit inside the abdominal cavity.
23. The human heart
creates enough pressure to squirt blood 30 feet: No wonder you can feel your heartbeat so easily. Pumping
blood through your body quickly and efficiently takes quite a bit of pressure
resulting in the strong contractions of the heart and the thick walls of the
ventricles which push blood to the body.
24. The acid in your
stomach is strong enough to dissolve razorblades: While you certainly shouldn’t test the fortitude of your
stomach by eating a razorblade or any other metal object for that matter, the acids that digest the
food you eat aren’t to be taken lightly. Hydrochloric acid, the type found in
your stomach, is not only good at dissolving the pizza you had for dinner but
can also eat through many types of metal.
25. The human body is
estimated to have 60,000 miles of blood vessels: To put that in perspective, the distance around the earth
is about 25,000 miles, making the distance your blood vessels could travel if
laid end to end more than two times around the earth.
26. You get a new
stomach lining every three to four days.
The mucus-like cells lining the walls of the stomach would soon dissolve due to
the strong digestive acids in your stomach if they weren’t constantly replaced.
Those with ulcers know how painful it can be when stomach acid takes its toll
on the lining of your stomach.
27. The surface area
of a human lung is equal to a tennis court: In
order to more efficiently oxygenate the blood, the lungs are filled with
thousands of branching bronchi and tiny, grape-like alveoli. These are
filled with microscopic capillaries which oxygen and carbon dioxide. The large
amount of surface area makes it easier for this exchange to take place, and
makes sure you stay properly oxygenated at all times.
28. Women’s hearts
beat faster than men’s.The main reason for
this is simply that on average women tend to be smaller than men and have less
mass to pump blood to. But women’s and men’s hearts can actually act quite
differently, especially when experiencing trauma like a heart attack, and many
treatments that work for men must be adjusted or changed entirely to work for
women.
29. Scientists have
counted over 500 different liver functions: You
may not think much about your liver except after a long night of drinking, but
the liver is one of the body’s hardest working, largest and busiest organs.
Some of the functions your liver performs are: production of bile,
decomposition of red blood cells, plasma protein synthesis, and detoxification.
30. The aorta is
nearly the diameter of a garden hose. The
average adult heart is about the size of two fists, making the size of the
aorta quite impressive. The artery needs to be so large as it is the main
supplier of rich, oxygenated blood to the rest of the body.
31. Your left lung is
smaller than your right lung to make room for your heart: For most people, if they were asked to draw a picture of
what the lungs look like they would draw both looking roughly the same size.
While the lungs are fairly similar in size, the human heart, though located fairly
centrally, is tilted slightly to the left making it take up more room on that
side of the body and crowding out that poor left lung.
32. You could remove
a large part of your internal organs and survive. The human body may appear fragile but it’s possible to
survive even with the removal of the stomach, the spleen, 75 percent of the
liver, 80 percent of the intestines, one kidney, one lung, and virtually every
organ from the pelvic and groin area. You might not feel too great, but the
missing organs wouldn’t kill you.
33. The adrenal
glands change size throughout life. The adrenal glands, lying
right above the kidneys, are responsible for releasing stress hormones like
cortisol and adrenaline. In the seventh month of a fetus’ development, the
glands are roughly the same size as the kidneys. At birth, the glands have
shrunk slightly and will continue to do so throughout life. In fact, by the
time a person reaches old age, the glands are so small they can hardly be seen.
Bodily Functions
We may not always like to talk about
them, but everyone has to deal with bodily functions on a daily basis. These
are a few facts about the involuntary and sometimes unpleasant actions of our
bodies.
34. Sneezes regularly
exceed 100 mph: There’s a good reason why
you can’t keep your eyes open when you sneeze–that sneeze is rocketing out of
your body at close to 100 mph. This is, of course, a good reason to cover your
mouth when you sneeze.
35. Coughs clock in
at about 60 mph: Viruses and colds get
spread around the office and the classroom quickly during cold and flu season.
With 60 mph coughs spraying germs far and wide, it’s no wonder.
36. Women blink twice
as many times as men do: That’s a lot of
blinking every day. The average person, man or woman, blinks about 13 times a
minute.
37. A full bladder is
roughly the size of a soft ball: No wonder
you have to run to bathroom when you feel the call of the wild. The average
bladder holds about 400-800 cc of fluid but most people will feel the urge to
go long before that at 250 to 300 cc.
38. Approximately 75%
of human waste is made of water: While we
might typically think that urine is the liquid part of human waste products,
the truth is that what we consider solid waste is actually mostly water as
well. You should be thankful that most waste is fairly water-filled, as drier
harder stools are what cause constipation and are much harder and sometimes
painful to pass.
39. Feet have 500,000
sweat glands and can produce more than a pint of sweat a day: With that kind of sweat-producing power it’s no wonder that
your gym shoes have a stench that can peel paint. Additionally, men usually
have much more active sweat glands than women.
40. During your
lifetime, you will produce enough saliva to fill two swimming pools: Saliva plays an important part in beginning the digestive
process and keeping the mouth lubricated, and your mouth produces quite a bit
of it on a daily basis.
41. The average
person expels flatulence 14 times each day: Even
if you’d like to think you’re too dignified to pass gas, the reality is that
almost everyone will at least a few times a day. Digestion causes the body to
release gases which can be painful if trapped in the abdomen and not released.
42. Earwax production
is necessary for good ear health: While
many people find earwax to be disgusting, it’s actually a very important part
of your ear’s defense system. It protects the delicate inner ear from bacteria,
fungus, dirt and even insects. It also cleans and lubricates the ear canal.
Sex and Reproduction
As taboo as it may be in some places,
sex is an important part of human life as a facet of relationships and the
means to reproduce. Here are a few things you might not have known.
43. On any given day,
sexual intercourse takes place 120 million times on earth: Humans are a quickly proliferating species, and with about
4% of the world’s population having sex on any given day, it’s no wonder that birth rates continue to
increase in many places all over the world.
44. The largest cell
in the human body is the female egg and the smallest is the male sperm: While you can’t see skin cells or muscle cells, the ovum is
typically large enough to be seen with the naked eye with a diameter of about a
millimeter. The sperm cell, on the other hand, is tiny, consisting of little
more than nucleus.
45. The three things
pregnant women dream most of during their first trimester are frogs, worms and
potted plants: Pregnancy hormones can
cause mood swings, cravings and many other unexpected changes. Oddly enough,
hormones can often affect the types of dreams women have and their vividness.
The most common are these three types, but many women also dream of water,
giving birth or even have violent or sexually charged dreams.
46. Your teeth start
growing 6 months before you are born: While
few babies are born with teeth in place, the teeth that will eventually push
through the gums of young children are formed long before the child even leaves
the womb. At 9 to 12 weeks the fetus starts to form the teeth buds that will
turn into baby teeth.
47. Babies are always
born with blue eyes: The color of your
eyes depends on the genes you get from your parents, but at birth most babies
appear to have blue eyes. The reason behind this is the pigment melanin. The
melanin in a newborn’s eyes often needs time after birth to be fully deposited
or to be darkened by exposure to ultraviolet light, later revealing the baby’s
true eye color.
48. Babies are, pound
for pound, stronger than an ox: While a
baby certainly couldn’t pull a covered wagon at its present size, if the child
were the size of an oxen it just might very well be able to. Babies have
especially strong and powerful legs for such tiny creatures, so watch out for
those kicks.
49. One out of every
2,000 newborn infants has a tooth when they are born: Nursing mothers may cringe at this fact. Sometimes the
tooth is a regular baby tooth that has already erupted and sometimes it is an
extra tooth that will fall out before the other set of choppers comes in.
50. A fetus acquires
fingerprints at the age of three months: When
only a small fraction of the way through its development, a fetus will have
already developed one of the most unique human traits: fingerprints. At only
6-13 weeks of development, the whorls of what will be fingerprints have already
developed. Oddly enough, those fingerprints will not change throughout the
person’s life and will be one of the last things to disappear after death.
51. Every human spent
about half an hour as a single cell: All
life has to begin somewhere, and even the largest humans spent a short part of
their lives as a single celled organism when sperm and egg cells first combine.
Shortly afterward, the cells begin rapidly dividing and begin forming the
components of a tiny embryo.
52. Most men have
erections every hour to hour and a half during sleep: Most people’s bodies and minds are much more active when
they’re sleeping than they think. The combination of blood circulation and testosterone
production can cause erections during sleep and they’re often a normal and
necessary part of REM sleep.
Senses
The primary means by which we interact
with the world around us is through our senses. Here are some interesting facts
about these five sensory abilities.
53. After eating too
much, your hearing is less sharp: If
you’re heading to a concert or a musical after a big meal you may be doing
yourself a disservice. Try eating a smaller meal if you need to keep your
hearing pitch perfect.
54. About one third
of the human race has 20-20 vision: Glasses
and contact wearers are hardly alone in a world where two thirds of the
population have less than perfect vision. The amount of people with perfect
vision decreases further as they age.
55. If saliva cannot
dissolve something, you cannot taste it: In
order for foods, or anything else, to have a taste, chemicals from the
substance must be dissolved by saliva. If you don’t believe it, try drying off
your tongue before tasting something.
56. Women are born
better smellers than men and remain better smellers over life: Studies have shown that
women are more able to correctly pinpoint just what a smell is. Women were
better able to identify citrus, vanilla, cinnamon and coffee smells. While
women are overall better smellers, there is an unfortunate 2% of the population
with no sense of smell at all.
57. Your nose can
remember 50,000 different scents: While a
bloodhound’s nose may be a million times more sensitive than a human’s, that
doesn’t mean that the human sense of smell is useless. Humans can identify a
wide variety of scents and many are strongly tied to memories.
58. Even small noises
cause the pupils of the eyes to dilate. It
is believed that this is why surgeons, watchmakers and others who perform
delicate manual operations are so bothered by uninvited noise. The sound causes
their pupils to change focus and blur their vision, making it harder to do
their job well.
59. Everyone has a
unique smell, except for identical twins: Newborns
are able to recognize the smell of their mothers and many of us can pinpoint
the smell of our significant others and those we are close to. Part of that
smell is determined by genetics, but it’s also largely do to environment, diet
and personal hygiene products that create a unique chemistry for each person.
Aging and Death
From the very young to the very old,
aging is a necessary and unavoidable part of life. Learn about the process with
these interesting, if somewhat strange facts.
60. The ashes of a
cremated person average about 9 pounds: A
big part of what gives the human body weight is the water trapped in our cells.
Once cremated, that water and a majority of our tissues are destroyed, leaving
little behind.
61. Nails and hair do
not continue to grow after we die. They do
appear longer when we die, however, as the skin dehydrates and pulls back from
the nail beds and scalp.
62. By the age of 60,
most people will have lost about half their taste buds: Perhaps you shouldn’t trust your grandma’s cooking as much
as you do. Older individuals tend to lose their ability to taste, and many find
that they need much more intense flavoring in order to be able to fully
appreciate a dish.
63. Your eyes are
always the same size from birth but your nose and ears never stop growing: When babies look up at you with those big eyes, they’re the
same size that they’ll be carrying around in their bodies for the rest of their
lives. Their ears and nose, however, will grow throughout their lives and
research has shown that growth peaks in seven
year cycles.
64. By 60 years of
age, 60-percent of men and 40-percent of women will snore. If you’ve ever been kept awake by a snoring loved one you
know the sound can be deafening. Normal snores average around 60 decibels, the
noise level of normal speech, intense snores can reach more than 80 decibels,
the approximate level caused by a jackhammer breaking up concrete.
65. A baby’s head is
one-quarter of it’s total length, but by age 25 will only be one-eighth of its
total length. As it turns out, our adorably
oversized baby heads won’t change size as drastically as the rest of our body.
The legs and torso will lengthen, but the head won’t get much longer.
Disease and Injury
Most of us will get injured or sick at
some point in our lives. Here are some facts on how the human body reacts to
the stresses and dangers from the outside world.
66. Monday is the day
of the week when the risk of heart attack is greatest: Yet another reason to loathe Mondays! A ten year study in
Scotland found that 20% more people die of heart attacks on Mondays than any
other day of the week. Researchers theorize that it’s a combination of too much
fun over the weekend with the stress of going back to work that causes the
increase.
67. Humans can make
do longer without food than sleep: While
you might feel better prepared to stay up all night partying than to give up
eating, that feeling will be relatively short lived. Provided there is water,
the average human could survive a month to two months without food depending on
their body fat and other factors. Sleep deprived people, however, start
experiencing radical personality and psychological changes after only a few
sleepless days. The longest recorded time anyone has ever gone without sleep is
11 days, at the end of which the experimenter was awake, but stumbled over
words, hallucinated and frequently forgot what he was doing.
68. A simple,
moderately severe sunburn damages the blood vessels extensively. How extensively? Studies have shown that it can take four
to fifteen months for them to return to their normal condition. Consider that
the next time you’re feeling too lazy to apply sunscreen before heading
outside.
69. Over 90% of
diseases are caused or complicated by stress: That high stress job you have could be doing more than just
wearing you down each day. It could also be increasing your chances of having a
variety of serious medical conditions like depression, high blood pressure and heart disease.
70. A human head
remains conscious for about 15 to 20 seconds after it is been decapitated: While it might be gross to think about, the blood in the
head may be enough to keep someone alive and conscious for a few seconds after
the head has been separated from the body, though reports as to the accuracy of this are
widely varying.
Muscles and Bones
Muscles and Bones provide the framework
for our bodies and allow us to jump, run or just lie on the couch. Here are a
few facts to ponder the next time you’re lying around.
71. It takes 17
muscles to smile and 43 to frown: Unless
you’re trying to give your face a bit of a workout, smiling is a much easier
option for most of us. Anyone who’s ever scowled, squinted or frowned for a
long period of time knows how it tires out the face which doesn’t do a thing to
improve your mood.
72. Babies are born
with 300 bones, but by adulthood the number is reduced to 206: The reason for this is that many of the bones of children
are composed of smaller component bones that are not yet fused like those in the skull. This makes
it easier for the baby to pass through the birth canal. The bones harden and
fuse as the children grow.
73. We are about 1 cm
taller in the morning than in the evening: The
cartilage between our bones gets compressed by standing, sitting and other
daily activities as the day goes on, making us just a little shorter at the end
of the day than at the beginning.
74. The strongest
muscle in the human body is the tongue: While
you may not be able to bench press much with your tongue, it is in fact the
strongest muscle in your body in proportion to its size. If you think about it,
every time you eat, swallow or talk you use your tongue, ensuring it gets quite
a workout throughout the day.
75. The hardest bone
in the human body is the jawbone: The next
time someone suggests you take it on the chin, you might be well advised to
take their advice as the jawbone is one of the most durable and hard to break
bones in the body.
76. You use 200
muscles to take one step: Depending on how
you divide up muscle groups, just to take a single step you use somewhere in
the neighborhood of 200 muscles. That’s a lot of work for the muscles
considering most of us take about 10,000 steps a day.
77. The tooth is the
only part of the human body that can’t repair itself: If you’ve ever chipped a tooth you know just how sadly true
this one is. The outer layer of the tooth is enamel which is not a living
tissue. Since it’s not alive, it can’t repair itself, leaving your dentist to
do the work instead.
78. It takes twice as
long to lose new muscle if you stop working out than it did to gain it: Lazy people out there shouldn’t use this as motivation to
not work out, however. It’s relatively easy to build new muscle tissue and get
your muscles in shape, so if anything, this fact should be motivation to get
off the couch and get moving.
79. Bone is stronger
than some steel: This doesn’t mean your
bones can’t break of course, as they are much less dense than steel. Bone has
been found to have a tensile strength of 20,000 psi while steel is much higher
at 70,000 psi. Steel is much heavier than bone, however, and pound for pound bone is the
stronger material.
80. The feet account
for one quarter of all the human body’s bones. You may not give your feet much thought but they are home to more
bones than any other part of your body. How many? Of the two hundred or so
bones in the body, the feet contain a whopping 52 of them.
Microscopic Level
Much of what takes place in our bodies
happens at a level that we simply can’t see with the naked eye. These facts
will show you that sometimes that might be for the best.
81. About 32 million
bacteria call every inch of your skin home: Germaphobes
don’t need to worry however, as a majority of these are entirely harmless and
some are even helpful in maintaining a healthy body.
82. Humans shed and
regrow outer skin cells about every 27 days: Skin protects your delicate internal organs from the elements and as
such, dries and flakes off completely about once a month so that it can
maintain its strength. Chances are that last month’s skin is still hanging
around your house in the form of the dust on your bookshelf or under the couch.
83. Three hundred
million cells die in the human body every minute: While that sounds like a lot, it’s really just a small
fraction of the cells that are in the human body. Estimates have placed
the total number of cells in the body at 10-50 trillion so you can afford to
lose a few hundred million without a hitch.
84. Humans shed about
600,000 particles of skin every hour: You
may not think much about losing skin if yours isn’t dry or flaky or peeling
from a sunburn, but your skin is constantly renewing itself and shedding dead
cells.
85. Every day an
adult body produces 300 billion new cells: Your
body not only needs energy to keep your organs up and running but also to
constantly repair and build new cells to form the building blocks of your body
itself.
86. Every tongue
print is unique. If you’re planning on committing
a crime, don’t think you’ll get away with leaving a tongue print behind. Each
tongue is different and yours could be unique enough to finger you as the
culprit.
87. Your body has
enough iron in it to make a nail 3 inches long: Anyone who has ever tasted blood knows that it has a
slightly metallic taste. This is due to the high levels of iron in the blood.
If you were to take all of this iron out of the body, you’d have enough to make
a small nail and very severe anemia.
88. The most common
blood type in the world is Type O: Blood
banks find it valuable as it can be given to those with both type A and B
blood. The rarest blood type, A-H or Bombay blood due to the location of its
discovery, has been found in less than hundred people since it was discovered.
89. Human lips have a
reddish color because of the great concentration of tiny capillaries just below
the skin. The blood in these capillaries
is normally highly oxygenated and therefore quite red. This explains why the
lips appear pale when a person is anemic or has lost a great deal of blood. It
also explains why the lips turn blue in very cold weather. Cold causes the
capillaries to constrict, and the blood loses oxygen and changes to a darker
color.
Miscellaneous
Here are a few things you might not
have known about all different parts of your anatomy.
90. The colder the
room you sleep in, the better the chances are that you’ll have a bad dream: It isn’t entirely clear to scientists why this is the case,
but if you are opposed to having nightmares you might want to keep yourself a
little toastier at night.
91. Tears and mucus
contain an enzyme (lysozyme) that breaks down the cell wall of many bacteria: This is to your advantage, as the mucus that lines your
nose and throat, as well as the tears that wet your eyes are helping to prevent
bacteria from infecting those areas and making you sick.
92. Your body gives
off enough heat in 30 minutes to bring half a gallon of water to a boil: If you’ve seen the Matrix you are aware of the energy
potentially generated by the human body. Our bodies expend a large amount of
calories keeping us at a steady 98.6 degrees, enough to boil water or even cook
pasta.
93. Your ears secrete
more earwax when you are afraid than when you aren’t: The chemicals and hormones released when you are afraid
could be having unseen effects on your body in the form of earwax. Studies have
suggested that fear causes the ears to produce more of the sticky substance,
though the reasons are not yet clear.
94. It is not
possible to tickle yourself: Even the most
ticklish among us do not have the ability to tickle ourselves. The reason behind this is that your
brain predicts the tickle from information it already has, like how your fingers
are moving. Because it knows and can feel where the tickle is coming from, your
brain doesn’t respond in the same way as it would if someone else was doing the
tickling.
95. The width of your
armspan stretched out is the length of your whole body: While not exact down to the last millimeter, your armspan
is a pretty good estimator of your height.
96. Humans are the
only animals to produce emotional tears: In
the animal world, humans are the biggest crybabies, being the only animals who
cry because they’ve had a bad day, lost a loved one, or just don’t feel good.
97. Right-handed
people live, on average, nine years longer than left-handed people do: This doesn’t have a genetic basis, but is largely due to
the fact that a majority of the machines and tools we use on a daily basis are
designed for those who are right handed, making them somewhat dangerous for
lefties to use and resulting in thousands of accidents and deaths each year.
98. Women burn fat
more slowly than men, by a rate of about 50 calories a day: Most men have a much easier time burning fat than women.
Women, because of their reproductive role, generally require a higher basic
body fat proportion than men, and as a result their bodies don’t get rid of
excess fat at the same rate as men.
99. Koalas and
primates are the only animals with unique fingerprints: Humans, apes and koalas are unique in the animal kingdom
due to the tiny prints on the fingers of their hands. Studies on primates have
suggested that even cloned individuals have unique fingerprints.
100. The indentation in
the middle of the area between the nose and the upper lip has a name. It is called the philtrum. Scientists have yet to figure
out what purpose this indentation serves, though the ancient Greeks thought it
to be one of the most erogenous places on the body.
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