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

Your heart rate slows when your face touches water. This is called the mammalian diving reflex.

2. One of the reasons your lungs feel refreshed when walking through a pine forest is because of an anti-inflammatory compound called a-Pinene, found in conifers. It is used as a bronchodilator in the treatment of asthma and is abundantly present in marijuana.

3. Some people can voluntarily cause a rumbling sound in their ears by tensing the tensor tympani muscle.

4. People with sensitive noses are capable of smelling when it's about to rain due to atmospheric chemicals reacting and creating ozone, which has a pungent, sweet smell.

5. There are nerve endings that exist only to recognize a gentle stroking touch. Their activation decreases the heart rate and activates the smile muscle. Their optimal speed is 3-5 cm/s, which means we are genetically wired to cuddle and caress each other at predetermined velocities.

Halting sneezing via blocking the nostrils and mouth is a dangerous maneuver. It may lead to numerous complications, such as pneumomediastinum (air trapped in the chest between both lungs), perforation of the tympanic membrane (perforated eardrum), and even cerebral aneurysm.

7. Humans don't actually have five senses, we have other senses like balance, heat, pain, and the passage of time. Humans actually have at least 14 senses.

8. Rh-null, the rarest blood type of the world, has been called the "Golden Blood". This blood type is so rare that only 43 people in the world have it, and there are only 9 active donors.

9. One person in four is a 'supertaster', who experiences the sensation of tasting more intensely. Supertasters have a high density of taste cells on their tongue but are likely to have a distaste for beer.

10. Low gravity makes it difficult to tell if your bladder is full because the bladder’s stretch receptor nerves don’t feel the weight of the liquid. Astronauts are trained to empty their bladders every two hours because of this.

When a healthy person donates a kidney, their other normal kidney will increase in size to compensate for the loss of the donated kidney.

12. The human anus is covered by cells similar to those in our mouths. That’s the reason you can feel the spicy foods down there just as much as in your mouth.

13. Human hair from hair salons which are rejected by wigmakers are being used to create oil adsorbing booms for ocean oil spills. Human hair can adsorb 3-9 times its own weight in oil.

14. Coughing while cleaning inside your ears is not something that everyone else experiences and is actually an uncommon reaction called Arnold’s Nerve Reflex.

15. You can count to 12 on one hand by using your thumb to count the bones of each finger. This might explain the base 12 and base 60 number systems we use for telling time and measuring angles.

The skin of all human beings is covered in stripes. They are called Blaschko’s Lines, and they cover the body from head to toe. We just can't see them.

17. When the liver fails to produce bile your poop doesn't get the regular brown pigments so it becomes white.

18. Heart cancer is not as common as other kinds of cancer because heart cells do not often undergo cell division, which reduces the chances of mutations that might ultimately lead to cancer.

19. Our pineal gland may be able to create, store, and release DMT after we die. This could explain why people who are revived tell about a type of out-of-body experience (bright tunnel, encountering deceased family members/friends).

20. Every person with blue eyes has a single common ancestor who lived 6000 to 10,000 years ago.

Our tonsils can have stones. They occur when food trapped in the crevices of our tonsils gets decomposed by bacteria that excrete calcium, phosphorus, magnesium, ammonia and carbonate that later solidifies. They are the leading cause of chronic halitosis.

22. Brushing your teeth can significantly reduce your risk of having a heart attack or stroke.

23. Due to their similar protein composition, blood can be used as an egg substitute in baking and making ice cream.

24. The tingling sensation some people experience in their mouth after eating pineapple is not an allergic reaction. It is their mouth being digested by an enzyme present in the pineapple.

25. The funny bone (ulnar nerve) is the largest unprotected nerve in the body.