The Human Body: 40 Surprising Facts Few Know – Part 4

A troubled intestine can send signals to the brain, just as a troubled brain can send signals to the gut. A person's stomach or intestinal distress can be the cause or the product of anxiety, stress, or depression due to the gastrointestinal (GI) system and brain connections.

27. If you have nerve damage to your hand or another body part, it won't wrinkle when submerged in water.

28. Earwax has antimicrobial properties which reduces the viability of bacteria and fungus in the human ear.

29. Post-workout muscles aren't sore because of lactic acid buildup. That’s a myth from a doctor who experimented on a severed frog. It’s actually a fuel made from glucose and burned by the muscles to maintain energy.

30. The human eye is different from most animals in that we have a large sclera, the white part of the eye. It's theorized that we evolved this so we could silently communicate where we are looking.

Our liver processes about 90% of the alcohol consumed and timewise the amount of alcohol the average adult can process within an hour is 10 ml of pure alcohol (one unit). Anything beyond the limit makes you "drunk."

32. Having an O-blood type makes you twice as likely to attract mosquitoes than people with A blood type. B blood types fall in the middle of the spectrum.

33. Within a split second, the human nose modifies the moisture of inhaled air to a constant relative humidity of 75%, and the temperature to a constant of 98.6°F (even if the air is 40°F or 100°F).

34. The extra layer of skin over the eye of 90% of Asiatic people is called the "epicanthic fold" and is theorized to have evolved as a protection against cold and snow blindness.

35. We don't sneeze in our sleep, because our "sneeze nerve" is sleeping as well.

Your liver has the ability to store a year’s worth of Vitamin B12. So if you change your lifestyle (becoming vegetarian) it may take years before symptoms are noticed when deficient.

37. When your eyes look right, your eardrums bulge to the left, and vice versa. However, scientists have discovered that the eardrums move 10 milliseconds before the eyes do, and they don't know why.

38. For every 200 million sperm in each human ejaculation, 2 million make it into the cervix, 1 million make it into the uterus, 10,000 make it to the top of the organ, 5,000 enter the uterotubal junction, 1000 enter the Fallopian tube, 200 reach the egg and only 1 enters the egg to fertilize it.

39. With an estimated 8,000 nerve endings, the clitoris is the only human organ that exists solely for pleasure.

40. The human liver has evolved to produce a dehydrogenase enzyme that knocks a hydrogen ion off of ethanol, detoxifying it and making it an easily absorbed aldehyde that human/animal bodies use as energy.