1. It's possible for your body to survive without a surprisingly large fraction of its internal organs. Even if you lose your stomach, your spleen, 75% of your liver, 80% of your intestines, one kidney, one lung, and virtually every organ from your pelvic and groin area, you wouldn't be very healthy, but you would live.
2. During your lifetime, you will produce enough saliva to fill two swimming pools. Actually, saliva is more important than you realize. If your saliva cannot dissolve something, you cannot taste it.
3. The largest cell in the human body is the female egg and the smallest is the male sperm. The egg is actually the only cell in the body that is visible by the naked eye.
4. The strongest muscle in the human body is the tongue and the hardest bone is the jawbone.
5. Human feet have 52 bones, accounting for one quarter of all the human body's bones.
6. Feet have 500,000 sweat glands and can produce more than a pint of sweat a day.
7. The acid in your stomach is strong enough to dissolve razor blades. The reason it doesn't eat away at your stomach is that the cells of your stomach wall renew themselves so frequently that you get a new stomach lining every three to four days.
8. The human lungs contain approximately 2,400 kilometers
(1,500 mi) of airways and 300 to 500 million hollow cavities, having a total surface area of about 70 square meters, roughly the same area as one side of a tennis court. Furthermore, if all of the capillaries that surround the lung cavities were unwound and laid end to end, they would extend for about 992 kilometers. Also, your left lung is smaller than your right lung to make room for your heart.
9. Sneezes regularly exceed 100 mph, while coughs clock in at about 60 mph.
10. Your body gives off enough heat in 30 minutes to bring half a gallon of water to a boil.
11. Your body has enough iron in it to make a nail 3 inches long.
12. Earwax production is necessary for good ear health. It protects the delicate inner ear from bacteria, fungus, dirt and even insects. It also cleans and lubricates the ear canal.
13. Everyone has a unique smell, except for identical twins, who smell the same.
14. Your teeth start growing 6 months before you are born. This is why one out of every 2,000 newborn infants has a tooth when they are born
15. A baby's head is one-quarter of its total length, but by the age of 25 will only be one-eighth of its total length. This is because people's heads grow at a much slower rate than the rest of their bodies.
16. Babies are born with 300 bones, but by adulthood the number is reduced to 206. Some of the bones, like skull bones, get fused into each other, bringing down the total number.
17. It's not possible to tickle yourself. This is because when you attempt to tickle yourself you are totally aware of the exact time and manner in which the tickling will occur, unlike when someone else tickles you.
18. Less than one third of the human race has 20-20 vision. This means that two out of three people cannot see perfectly.
19. Your nose can remember 50,000 different scents. But if you are a woman, you are a better smeller than men, and will remain a better smeller throughout your life.
20. The human body is estimated to have 60,000 miles of blood vessels.
21. The three things pregnant women dream most of during their first trimester are frogs, worms and potted plants. Scientists have no idea why this is so, but attribute it to the growing imbalance of hormones in the body during pregnancy.
22. The life span of a human hair is 3 to 7 years on average. Every day the average person loses 60-100 strands of hair. But don't worry, you must lose over 50% of your scalp hairs before it is apparent to anyone.
23. The human brain cell can hold 5 times as much information as an encyclopedia. Your brain uses 20% of the oxygen that enters your bloodstream, and is itself made up of 80% water. Though it interprets pain signals from the rest of the body, the brain itself cannot feel pain.
24. The tooth is the only part of the human body that can't repair itself.
25. By 60 years of age, 60% of men and 40% of women will snore.
26. We are about 1 cm taller in the morning than in the evening, because during normal activities during the day, the cartilage in our knees and other areas slowly compress.
27. The brain operates on the same amount of power as 10-watt light bulb, even while you are sleeping. In fact, the brain is much more active at night than during the day.
28. Nerve impulses to and from the brain travel as fast as 170 miles per hour. Neurons continue to grow throughout human life. Information travels at different speeds within different types of neurons.
29. It is a fact that people who dream more often and more vividly, on an average have a higher Intelligence Quotient.
30. The fastest growing nail is on the middle finger.
31. Facial hair grows faster than any other hair on the body. This is true for men as well as women.
32. There are as many hairs per square inch on your body as a chimpanzee.
33. A human fetus acquires fingerprints at the age of three months.
34. By the age of 60, most people will have lost about half their taste buds.
35. About 32 million bacteria call every inch of your skin home. But don't worry, a majority of these are harmless or even helpful bacteria.
36. The colder the room you sleep in, the higher the chances are that you'll have a bad dream.
37. Human lips have a reddish color because of the great concentration of tiny capillaries just below the skin.
38. Like fingerprints, every individual has an unique tongue print that can be used for identification.
39. It takes 17 muscles to smile and 43 to frown.
40. Humans can make do longer without food than sleep. 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.
41. The most common blood type in the world is Type O. 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
42. Every human spent about half an hour after being conceived, as a single cell. Shortly afterward, the cells begin rapidly dividing and begin forming the components of a tiny embryo.
43. Humans are the only animals to produce emotional tears.
44. The human heart creates enough pressure to squirt blood 30 feet in the air.