The human body, an endless stream of wonders and amazement. An incredibly complex and intricate system, it is one well that humanity still hasn’t managed to get to the bottom of, despite thousands of years of medical knowledge. Our body might just be the perfect machine, as electronic music pioneers Kraftwerk used to sing. So, as a tribute to the machine carrying all of our dreams, desires, emotions and fantasies, here are the fifty most incredible facts about the human body you might not have known – from the brain, all the way to the bodily functions and reproductive processes.
1. Nerve impulses to and from the brain travel as fast as 170 miles per hour. This is the reason why we can react to things around us right away and why a stubbed toe hurts instantly.
2. The brain operates on the same amount of power as a 10-watt 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 and 1,000 terabytes. For comparison, The National Archives of Britain, containing over 900 years of history, only take up 70 terabytes.
4. The brain uses 20% of the oxygen that enters the 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.
5. The brain is much more active at night than during daytime. Even with all the information it has to process during the day, the brain’s activity levels are still much lower compared to those while you dream.
6. Scientists say the higher your I.Q. the more you dream. This does not mean you are you are 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 have thought that brain and neural tissue could not 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 several different types within the body and transmission along them 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 or burn yourselves, the brain itself does not have pain receptors. That doesn’t mean your head can’t hurt. The brain is surrounded by loads of tissues, nerves and blood vessels that are receptive to pain and can give headaches.
10. 80% of the brain is water. Your brain isn’t the firm, gray mass you’ve seen on television. Living brain tissue is a squishy, pink and jelly-like organ thanks to loads of blood and high water content of the tissue.
Hair and Nails
11. Facial hair grows faster than any other hair on the body. If an average man never shaved his beard during his lifetime, it would grow to over 30 feet, longer than a killer whale.
12. Every day the average person loses 60-100 strands of hair. Hair loss varies in accordance with the season, pregnancy, illness, diet and age.
13. Women’s hair is about half the diameter of men’s hair. 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 – 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 the one on the middle finger, with the one on one’s dominant hand growing fastest of all. It is not entirely known why, but nail growth is related to finger length, 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 on a chimpanzee’s. The reason human bodies don’t appear as hair-covered as apes’ is that on most of us the hair is not as obvious as a majority of the strands are too fine or light to be seen.
17. Blondes 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. Despite losing hair every day, your hairs actually have a pretty long life providing they aren’t subject to any trauma. Most of your hairs will likely get to see several different haircuts, styles, and even possibly decades before they fall out on their own.
20. A person must lose over 50% of their scalp hairs before it is apparent to anyone. An average person loses hundreds of hairs a day but they would need to lose a lot more before anyone else notices.
21. Human hair is virtually indestructible. Aside from its flammability, human hair decays at such a slow rate that it is practically non-disintegrative. 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.
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. To pump blood through the body quickly and efficiently quite a bit of pressure is needed, resulting in the strong contractions of the heart and the thick walls of the ventricles.
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, hydrochloric acid, the type found in the 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 transfer the oxygen to the bloodstream and release carbon dioxide. This 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 and vice versa.
29. Scientists have counted over 500 different liver functions as 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. The left lung is smaller than the right lung to make room for the 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 taking up more room on that side of the body.
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.
33. The adrenal glands change size throughout life. Lying right above the kidneys, they 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.
34. 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 enough reason to cover your mouth when sneezing.
35. Coughs clock in at about 60 mph. That’s why viruses and colds get spread around the office and the classroom quickly during cold and flu season.
36. Women blink twice as many times as men do. The average person, man or woman, blinks about 13 times a minute.
37. A full bladder is roughly the size of a soft ball. The average bladder holds about 400-800 cc of fluid but most people will feel the urge to go at 250 to 300 cc.
38. Approximately 75% of human waste is made of water. While most of us perceive urine as the liquid part of human waste products, incredibly, solid waste is actually mostly water as well.
39. Feet have 500,000 sweat glands and can produce more than a pint of sweat a day. 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.
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 unsightly, it’s actually a very important part of the 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
43. On any given day, sexual intercourse takes place 120 million times on earth. With about 4% of the world’s population having sex on any given day, it is little wonder that birth rates continue to increase in many places around 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 a 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. 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 the eyes of a newborn 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, 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, that’s why their kicks are felt by pregnant mothers.
49. One out of every 2,000 newborn infants has a tooth when they are born. 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 teeth comes in.
50. A fetus acquires fingerprints at the age of three months. At only 6-13 weeks of development, the whirls 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.