100 Incredible 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 shouldnÕt
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 human brain is the most complex and least understood
part of the human anatomy. There may be a lot we donÕt know, but here are a
few interesting facts that weÕve 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? ItÕs
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 isnÕt too far off the mark. Your brain
generates as much energy as a small light bulb even when youÕre 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 brainÕs
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 donÕt 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, donÕt take it as a sign youÕre
mentally lacking if you canÕt recall your dreams. Most of us donÕt 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 couldnÕt
grow or regenerate. While it doesnÕt 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 doesnÕt mean your head canÕt 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 isnÕt the firm,
gray mass youÕve 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 youÕre feeling dehydrated get a drink to keep your
Hair and Nails
While theyÕre not a living part of your body, most people
spend a good amount of time caring for their hair and nails. The next time
youÕre heading in for a haircut or manicure, think of these facts.
11. Facial hair grows faster than any
other hair on the body. If
youÕve ever had a covering of stubble on your face as youÕre clocking out
at 5 oÕclock youÕre 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 youÕre already bald, chances are good that youÕre
shedding pretty heavily on a daily basis. Your hair loss will vary in
accordance with the season, pregnancy, illness, diet and age.
13. WomenÕs hair is about half the
diameter of menÕs hair. While
it might sound strange, it shouldnÕt come as too much of a surprise that
menÕs hair should be coarser than that of women. Hair diameter also varies
on average between races, making hair plugs on some men look especially
14. One human hair can support 3.5
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
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 weÕre
made out to be. We have lots of hair, but on most of us itÕs not obvious as
a majority of the hairs are too fine or light to be seen.
17. Blondes have more hair. TheyÕre 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 personÕs
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
18. Fingernails grow nearly 4 times
faster than toenails. If
you notice that youÕre trimming your fingernails much more frequently than
your toenails youÕre 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 arenÕt 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 youÕll 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
from itÕs flammability, human hair decays at such a slow rate that it is
practically non-disintegrative. If youÕve 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.
Though we may not give them much thought unless theyÕre
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 werenÕt
looped back and forth upon itself it wouldnÕt fit inside the abdominal
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 shouldnÕt 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 arenÕt 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 werenÕt 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
28. WomenÕs hearts beat faster than
reason for this is simply that on average women tend to be smaller than men
and have less mass to pump blood to. But womenÕs and menÕs 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 bodyÕs 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 itÕs 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 wouldnÕt 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 fetusÕ 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.
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. ThereÕs a good reason why you
canÕt 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, itÕs no wonder.
36. Women blink twice as many times
as men do. ThatÕs
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 itÕs no wonder that your gym shoes have a stench that
can peel paint. Additionally, men usually have much more active sweat glands
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 youÕd like to think youÕre 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, itÕs actually a very important
part of your earÕs defense system. It protects the delicate inner ear from
bacteria, fungus, dirt and even insects. It also cleans and lubricates the
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 worldÕs population having
sex on any given day, itÕs 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 canÕt 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
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
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
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 newbornÕs eyes often needs time after
birth to be fully deposited or to be darkened by exposure to ultraviolet
light, later revealing the babyÕs true eye color.
48. Babies are, pound for pound,
stronger than an ox. While
a baby certainly couldnÕt 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 personÕs 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 peopleÕs bodies and minds are much more
active when theyÕre sleeping than they think. The combination of blood
circulation and testosterone production can cause erections during sleep
and theyÕre often a normal and necessary part of REM sleep.
The primary means by which we interact with the world around
us is through our senses. Here are some interesting facts about these five
53. After eating too much, your
hearing is less sharp. If
youÕre 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 donÕt
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 bloodhoundÕs nose may be a million times more sensitive than a humanÕs,
that doesnÕt 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
itÕs 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 shouldnÕt trust
your grandmaÕs 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, theyÕre the same size that theyÕll 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
inseven year cycles.
64. By 60 years of age, 60-percent of
men and 40-percent of women will snore. If youÕve 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 babyÕs head is one-quarter of
itÕs total length, but by age 25 will only be one-eighth of its total
length. As it
turns out, our adorably oversized baby heads wonÕt change size as drastically
as the rest of our body. The legs and torso will lengthen, but the head
wonÕt 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! Aten 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 itÕs 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 youÕre 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 ofserious 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 youÕre lying around.
71. It takes 17 muscles to smile and
43 to frown. Unless
youÕre trying to give your face a bit of a workout, smiling is a much
easier option for most of us. Anyone whoÕs ever scowled, squinted or frowned
for a long period of time knows how it tires out the face which doesnÕt 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
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
on how you divide up muscle groups, just to take a single step you use
somewhere in the neighborhood of 200 muscles. ThatÕs 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 canÕt repair itself. If youÕve 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 itÕs not alive, it canÕt 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
shouldnÕt use this as motivation to not work out, however. ItÕs 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
79. Bone is stronger than some steel. This doesnÕt mean your bones
canÕt 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 bodyÕs 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.
Much of what takes place in our bodies happens at a level
that we simply canÕt 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 donÕt need to worry however, as a majority
of these are entirely harmless and some are even helpful in maintaining a
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 monthÕs 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, itÕs 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
isnÕt 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
86. Every tongue print is unique. If youÕre planning on
committing a crime, donÕt think youÕll 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, youÕd 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
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.
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 youÕll have a bad dream. It isnÕt 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
92. Your body gives off enough heat
in 30 minutes to bring half a gallon of water to a boil. If youÕve 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 arenÕt. 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
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 doesnÕt
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 theyÕve had a bad day, lost a loved
one, or just donÕt feel good.
97. Right-handed people live, on
average, nine years longer than left-handed people do. This doesnÕt 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 donÕt 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.
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.