The human body is a wild and complicated machine. There are all sorts of strange facts about the body that you’ve probably never heard before. We’ve chosen 60 of the most interesting ones to share with you today. Some of them will literally blow your mind. For example, we’ll teach you about Exploding Head Syndrome. Yes, it’s real!
Other facts are just as fascinating. From the help blowing on your thumb gives to learning about how far your heart can squirt blood across a room, this list has it all. You might be surprised by just how much you don’t know about yourself.
1. Human teeth are as strong as shark teeth.
Although the
teeth of sharks are made from a harder mineral than human teeth, they are still similar in strength. It is largely due to the enamel coating on them. The enamel is comparable in each species.
2. When people blush, so does their stomach lining.
Both the human stomach and the face become red when
blushing. It’s because it causes all of your capillaries in your body widen. The increased blood flow is responsible for the red color.
3. The brain generates enough electricity to power a light bulb.
There is a lot going on up there. The
brain is constantly sending electrical signals and impulses between the billions of neurons. Combine them all together and you can power a low-watt bulb.
4. Having your heart broken actually causes a heart condition.
It is called
broken heart syndrome and it’s entirely real. The emotional stress can cause chest pain and shortness of breath similar to a heart attack. It normally resolves within a few days or weeks.
5. Humans can make up to 7,000 different facial expressions.
We have many more facial
muscles than our primate ancestors. Also, part of having no hair on the face means that our expressions are easier to see too. There are thousands of different possibilities.
6. Some people hear the sound of a bomb going off when falling asleep.
The name for this weird experience is
exploding head syndrome. It sounds like a loud gunshot or explosion and happens upon sleeping or awakening. It has been estimated that it affects up to 10% of the population.
7. Human hair is pretty much indestructible.
One of the only real threats to
hair is fire. Besides that, it decays at an extremely slow rate. It’s even resistant to various types of chemicals and acids.
8. There is a syndrome where people become obsessed with fine dining.
It’s called
Gourmand Syndrome. It happens due to an injury of the right anterior cerebral hemisphere of the brain. Afterward, the individual will show a preference for eating and thinking about fine foods.
9. Stomach acid is strong enough to burn a hole in your skin.
Individual stomachs vary in levels of
acidity. However, the hydrochloric acid produced by your body is not only strong enough to break down food but in many cases, it can even bore through a piece of wood.
10. You can reduce stress by putting your thumb up to your mouth and blowing
It sounds strange, but blowing on your
thumb is a great stress reliever. It works by cooling off the thumb and calming the pulse in it. This, in turn, causes your body to feel more relaxed in general.
11. There is likely more bacteria in your mouth than people living on Earth.
The bacteria love the warm and moist environment. It thrives in there. There are at least 615 documented types of
bacteria you might find, and their levels in your mouth can number in the billions.
12. Babies have more bones in their bodies than adults do.
Humans are born with at least 300 or more
bones. However, many of these fuse together slowly over time. Adults ultimately end up with a total of 212 different bones.
13. If laid side by side, the length of your blood vessels would circle the world more than twice.
Between the arteries, veins, and capillaries, there are a lot of
blood vessels in the body. They are winding all throughout every inch of your limbs. Line them up and they would likely stretch between 60 to 100 thousand miles.
14. The human eye can see at a resolution of 500 megapixels.
This
estimate includes your whole field of vision spanning 180 degrees. It would take a very high definition camera to match this. The eye is superior to most devices.
15. There is ten times as much bacteria in the body as there are human cells.
Bacteria is much more plentiful than actual cells. The giant
microbial communities have a serious effect on health. Yet, they are still largely unstudied by scientists.
16. Your skin makes up around 16% of your body weight.
In the average adult, that means around 20 pounds or more of just
skin. If you peeled it off and lined it up, it would cover an area of about 22 square feet. Now that is a lot of skin!
17. There are mites living on your eyelashes.
They inhibit other hair follicles too. It’s a little weird to think about. The species of mites is known as
Demodex, and it’s possible that they are what is behind various skin disorders.
18. Every ten years, the human skeleton regenerates itself.
The bones are regenerating around the clock. At any one time, there is a large mix of old and new
bones in the body. The process never stops, but as we age, it does slow down.
19. The heart can squirt blood up to thirty feet in distance.
It is a living pump with a lot of
pressure that can send blood flying all the way across a room. It is very strong. The heart pumps around 2000 gallons of blood every day.
20. Our eyes are closed 10% of the time that we are awake.
This is mostly made up of the time spent
blinking. A blink only lasts a split second, but we do it a lot. The average person blinks around 15 to 20 times per minute.
21. The heart can continue beating once taken out of the body.
That is how they do heart
transplants. The doctors keep the heart beating while they transport it to the receiving patient. The procedure is completed about 5,000 times every year worldwide.
22. All of your blood gets filtered by your kidney 25 times per day.
It comes out to around 180 liters of
blood processed daily. The average body contains seven or eight liters in total. The kidney filtration is crucial to keeping your blood healthy.
23. There is a type of tumor that grows on teeth and hair.
We normally think about tumors growing on the skin or organs. However, there is a type of cyst called
teratoma that involve tissues like bone, hair, and teeth. They can be removed by surgery.
24. The pink corner in your eyes is related to bird and reptile species.
It is an evolutionary remnant from the past. It used to be an inner
eyelid similar to those that birds and reptiles have. After millions of years of evolution, there is not much left.
25. You are shorter at night when you go to bed.
Your height is the
tallest first thing in the morning when you wake up. Over the course of the day, your spine gets compressed. There is a gelatin-like material in between your discs that acts as a cushion. It moves around while you sleep.
26. The liver can regenerate to its full size even if 75% is removed.
Take away three quarters of the
liver and it can still survive. It will slowly grow back over time. It is the only organ in the body that has the capacity to regenerate.
27. Every ten years after age 30, you lose about a half an inch in height.
As people grow older, they also get
shorter. It’s because the discs between the vertebrae start to flatten. It happens very slowly and most won’t even notice the change in height.
28. The human heartbeat can synchronize with music.
Depending on the beat and tempo of the music you are listening to, your
heart beat will speed up or slow down. Songs that have crescendos in them can cause blood vessels in the cardiovascular system to constrict.
29. You lose around half of your taste buds by age 60.
Humans begin with about 10,000
taste buds. However, due to age, the way things taste changes over time. Taste buds really only last around ten days before changing.
30. The enzymes that digest food also digest your body after you die.
After death, the
enzymes begin working on you. The microbial organisms can feed on the fluids produced during autolysis — the process that occurs once you pass away.
31. Kissing can help prevent cavities.
When you
kiss, your mouth produces more saliva. Getting your fluids secreting like this helps to wash away plaque. Less plaque means fewer cavities.
32. Humans are made of stardust dating back billions of years.
People have about 97% of the same
atoms as the galaxy that we live in. As a result of supernovas, stars explode and the dust forms into new planets, and ultimately, people. Around 93% of the
mass of the body is actually stardust.
33. Humans glow in the dark.
Our bodies are
bioluminescent, meaning in the dark, we give off light. It’s just too faint to be seen by the human eye. Species like fireflies and some jellyfish exhibit this property much more strongly.
34. In a lifetime, the heart pumps about 200 million liters of blood.
The heart
contracts over 100,000 times every day. It is always pumping away. With exercise, it pumps up to six times as fast as normal too.
35. In the 1940’s, most people dreamed in black and white.
About three-quarters of Americans reported that they almost never saw
color in their dreams back then. It is believed to be because of the exposure to black and white television and films. The percentage of people that report this phenomenon now is much smaller.
36. The mouth produces one to two liters of spit every day.
It’s enough to fill two to four water bottles. Your
salivary glands can be triggered just by thinking about food. When you are eating, they work even harder.
37. When you are submerged in water, your body triggers a “diving reflex”.
It causes certain systems in the body to shut down and conserve energy. There are actual physiological changes. It is clear from the
research that humans have a long aquatic history.
38. If you untwisted all of your DNA, it would be long enough to traverse the solar system twice.
DNA is made up of long coils. If unwound, your
DNA would stretch all the way from Earth to Pluto and back again. In every single cell, there is about 2 meters worth of DNA.
39. Tears have a different composition depending on whether they were shed for sadness or happiness.
The emotion that causes the
tears to form matters. There are a total of three different types of tears. Each of them looks different when examined under a microscope.
40. There is enough fat in the human body to make ten bars of soap.
This obviously varies on a person to person basis. Some people could be made into more or less
soap. It all depends on the supply of fat reserves that they have.
41. The brains of women shrink during pregnancy.
After childbirth it can take six months before the
brain returns to its normal size. It’s not a big change, but it is observable. Once the baby is delivered, the changes begin to slowly reverse.
42. The cornea of the eye doesn’t have its own blood supply.
It is the only part of the body that doesn’t receive blood. It’s because it doesn’t need it. The
cornea receives oxygen directly from the air it is exposed to instead.
43. The first thing to develop in a human embryo is the anus.
You would think it would be the brain or literally anything else. However, it’s
true. The second thing to develop is the mouth, which we suppose makes sense.
44. The fingerprints of a human embryo develop after three months.
By the 17th week of pregnancy, the
fingerprints are pretty much set in stone. After this point, they won’t ever change for the rest of a person’s life. Every fingerprint is completely unique.
45. Your feet contain a quarter of your body’s bones.
Each foot and ankle has a total of 26
bones. There are also 33 joints and over 100 muscles, tendons, and ligaments. It is an extremely complex area of your skeletal system.
46. Astronauts sometimes grow as much as two inches taller in space.
Without gravity weighing down on your body all of the time, it can stretch out. Most
astronauts come back from space slightly taller than before. The one who gained two inches was on the space station for about a year.
47. The small intestine is about 20 feet long.
In addition, the large intestine of humans is around five feet long. If you combine both
intestines together, it would make a rope that is long enough to repel out of a three-story building.
48. If you are starving, the brain will begin to eat itself.
This situation can even be caused by extreme dieting. The scientific term for it is
autophagy. It’s when the cells in the body start to consume small portions of themselves.
49. Your brain can survive for five to ten minutes with zero oxygen.
You will pass out after a minute or two of no oxygen. However, your
brain will continue functioning a while after that. Even after the heart stops, it will still take about six more minutes for brain death to occur.
50. If you have two of an organ, only one is required to live.
For example, if you lose one of your lungs, you can still live a perfectly normal
life. You just won’t be able to exercise as vigorously. The same idea applies to kidneys.
51. The left kidney is higher up than the right one.
While on the topic of organs, it’s important to realize they aren’t always entirely symmetrical either. The position of the
kidneys in the body is different. It’s pretty interesting.
52. It’s not possible to swallow and breathe at the same time.
A lot of other animals can. However, not
humans. It’s because of the placement of our voice box. It’s either one or the other.
53. If the brain was laid out flat, it would cover a whole pillowcase.
The head is pretty tiny, but the
brain takes up a lot more space than most people think. You would have to smooth out all of the wrinkles though to realize how big it is.
54. It’s possible your body has previously fought off cancer.
You wouldn’t necessarily even know. Your
cells are constantly dividing, but the body is pretty good at catching errors. If a cell notices that something is wrong, it is normally able to realize it’s broken and commit suicide before it gets out of control.
55. Your tongue print is as unique as a fingerprint.
They probably won’t start asking you to do a print of your
tongue in police stations anytime soon though. The tongue print needs to be recorded using a 3D imaging machine. They aren’t exactly cheap.
56. Babies blink significantly less than adults do.
An average adult blinks about ten times per minute. However, a
baby will only blink once or twice in the same amount of time. They rarely close their eyes when they are awake.
57. Humans shed around 600,000 particles of skin each hour.
Every year, people lose about 1.5 pounds worth of
skin. Over a lifetime, it works out to over 100 pounds. Although, day by day, it’s barely noticeable.
58. The strongest muscle in the human body is the jaw muscle.
It depends on how you measure strength. However, based on weight, the
jaw muscle comes in first place. It can help your molars to chomp down with as much as 200 pounds of force.
59. Every body contains about three to five pounds of bacteria.
You carry the
bacteria around with you everywhere that you go. It’s enough to fill a whole soup can. All in all, the bacteria make up around one to two percent of body mass.
60. The highest ever recorded fever measured 115 degrees Fahrenheit.
The individual
survived. Normal human body temperature is 98.6° F. Anything above 100.4 is concerning. For most people, once you hit around 107, multiple organ failure starts to occur.
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