By Meenambika Menon
The human body is one of the most complicated and fascinating living forms on Earth. Here are some interesting features that make it special, which you can share with your kids.
1. Adult lungs have a surface area of around 70 square metres.
2. Your left and right lungs aren’t exactly the same. The lung on the left side of your body is divided into two lobes while the lung on your right side is divided into three. The left lung is also slightly smaller, allowing room for your heart.
3. Human lungs contain almost 1,500 miles of airways and over 300 million alveoli.
4. An average person breathes in around 11,000 litres of air every day.
5. Your nose and ears continue growing throughout your entire life.
6. Your sense of smell is around 10,000 times more sensitive than your sense of taste.
7. Around 80 per cent of what we think is taste is actually smell. Flavour, is a combination of taste and smell perception.
8. The brain uses over a quarter of the oxygen used by the human body.
9. The brain of an adult human weighs around 3 pounds (1.5 kg). Although it makes up just 2 per cent of the body’s weight, it uses around 20 per cent of its energy.
10. If you smoothed out all of the wrinkles in your brain, it would lay flat the size of a pillowcase.
11. Your heart beats around 100,000 times a day, 365,00,000 times a year and over a billion times if you live beyond 30.
12. Grouping human blood types can be a difficult process and there are currently around 30 recognised blood types (or blood groups). You might be familiar with the more simplified “ABO” system which categorises blood types under O, A, B and AB.
13. When listening to music, your heartbeat will sync with the rhythm.
14. An healthy adult human heart beats about 75 times on average in a minute.
15. In one year, a human heart would pump enough blood to fill an Olympic size pool.
16. If all the blood vessels in the human body were laid end to end, they would encircle the Earth four times.
17. Skin is the human body’s largest organ
18. The outer layer of your skin is the epidermis, it is found thickest on the palms of your hands and soles of your feet (around 1.5 mm thick).
19. A large amount of the dust in your home is actually dead skin. Humans shed about 600,000 particles of skin every hour.
20. Humans have a stage of sleep that features rapid eye movement (REM). REM sleep makes up around 25 per cent of total sleep time and is often when you have your most vivid dreams.
21. An eyelash lives for about 150 days before it falls out.
22. The smallest bone found in the human body is located in the middle ear. The staples (or stirrup) bone is only 2.8 millimetres long.
23. The femur (thigh bone) is the longest bone in the human body.
24. As well as having unique fingerprints, humans also have unique tongue prints.
25. Goose bumps evolved to make our ancestors’ hair stand up, making them appear more threatening to predators.
26. Humans are the only animals with chins.
27. Blushing is caused by a rush of adrenaline.
28. The cornea is the only part of the body with no blood supply – it gets its oxygen directly from the air.
29. The human body contains enough fat to make seven bars of soap.
30. Between birth and death, the human body goes from having 300 bones, to just 206.
31. The small intestine is roughly 23 feet long.
32. An average sized man eats about 33 tons of food in his/her life time which is about the weight of six elephants.
33. Nephrons, the kidney’s filtering units, clean the blood in the human body in about 45 minutes and send about six cups of urine (2000 ml) to the bladder every day.
34. One quarter of your bones are in your feet.
35. You can’t breathe and swallow at the same time.
36. The average person produces enough saliva in their lifetime to fill two swimming pools.
37. There are about ten thousand taste buds on the human tongue and in general girls have more taste buds than boys!
38. While awake, your brain produces enough electricity to power a lightbulb.
39. The left side of your brain controls the right side of your body and right side of your brain controls the left side of your body.
40. In camera terms, the human eye is about 576 megapixels.
41. Our brain is programmed to erect the inverted image formed on our retina by the convex eye lens. A newborn baby sees the world upside down till its brain starts erecting it.
42. You carry, on average, about four pounds of bacteria around in your body.
43. 50 percent of your hand strength comes from your little finger.
44. Sometimes the pain from scratching makes your body release the pain-fighting chemical serotonin. It can make the itch feel even itchier.
45. As people get older, their skin gets thinner, drier, and less elastic, hence wrinkles start appearing.
46. An adult skin weighs around 3 to 4 kgs.
47. If you spread out your skin, it would measure around 20 square feet in size, about the same size as a child’s bed sheet.
48. Diaphragm, which is a thin membrane under the lungs, sometimes twitches, causing a sudden intake of air, which is interrupted by throat closing. This is what we call hiccups.
49. In case of injury under the skin the blood vessels break and spread into the tissues near the injury. The dark colour of the blood shows through the skin as bruise.
50. A running nose is the way our body flushes out germs from our nose while we catch cold and flu.
51. On average, human body contains enough iron to make a nail 2.5 cm (1 inch) long.
(Source: With inputs from allthatsinteresting.com, mentalfloss.com and The New Children’s Encyclopedia DK Publication.)
(The writer is Lead, Curriculum – Science & Math at Shiv Nadar School.)