Human blood is an incredibly important fluid. Without this fluid, no human can survive. One of the most important functions of blood is to carry oxygen to different parts of the body.

In absence of blood, body will fail to receive any oxygen which will result in death. But is that the only function of blood? Not really! There are other important functions too.

Let us learn 80 interesting human blood facts in order to find out some really amazing facts about this fascinating body fluid. We are sure, you will be surprised! Are you ready?

Interesting Human Blood Facts 1-5

1. Nearly 7% of the body weight of a human is made up of blood.

2. Platelets, white blood cells and red blood cells are present in blood.

3. Blood consists of a yellow liquid which is known as blood plasma.

4. Blood plasma is primarily made up of water. 90% of blood plasma is water.

5. Blood plasma also consists of hormones, glucose, proteins, gases, electrolytes and nutrients.

Interesting Human Blood Facts 6-10

6. Platelets, white blood cells and red blood cells are all found floating in blood plasma.

7. Blood plasma can be separated using centrifuge device which spins blood at a very high speed. The cells then get collected at the bottom of the tube, separating blood plasma from the cells.

8. Only the red blood cells in our blood are responsible for carrying oxygen.

9. Red blood cells consist of hemoglobin. Hemoglobin is actually a protein that contains iron. Oxygen combines with this iron and gives the characteristic red color to our blood as well as hemoglobin.

10. Unlike red blood cells, the white blood cells in our blood form the defensive system of our body. These white blood cells are responsible for fighting viruses, bacteria and other infectious diseases. They also fight cancer cells and other unwanted material that enter human body.

Interesting Human Blood Facts 11-15

11. Platelets are completely different and are responsible for blood clotting whenever bleeding occurs because of a cut or bruise. This prevents unwanted loss of blood.

12. While blood clotting is meant for good, it can become dangerous. If blood clots in blood vessels of heart, one can experience heart attack. Similarly, blood clot in brain can lead to stroke.

13. Blood is not just responsible for carrying oxygen to different parts of the body. It also carries nutrients to body cells. At the same time, it also carries away unwanted waste material away from the cells.

14. Blood pressure is actually the pressure exerted by blood on blood vessel walls. BP is a vital sign of life.

Interesting Human Blood Facts 16-20

15. High BP implies increased risk of stroke and heart attack.

16. Average blood pressure will always vary from one person to another despite the fact that standard considered BP is 112/64 mmHg.

17. Though we are familiar with common blood types A, B, AB and O, which is a part of simplified ABO system, there are actually around 30 different recognized blood groups or blood types.

18. An adult body has 100,000 kilometers or 60,000 miles of blood vessels running throughout the body.

19. The average volume of blood present in an adult male body is 5.6 liters while an adult female body contains 4.5 liters of blood on an average.

20. A new born baby will have around 1 cup of blood in its body.

Interesting Human Blood Facts 21-25

21. Blood plasma we mentioned earlier makes up around 55% of the total volume of blood present in human body.

22. Blood consists of a special type of white blood cell known as granulocyte. These cells roll along blood vessel walls and hunt for bacteria. If they find any harmful bacteria, granulocytes will destroy these bacteria by engulfing them.

23. Red blood cells survive in circulatory system for no more than 120 days.

24. Platelets, plasma and red blood cells are constantly produced by bone marrow.

25. Donated red blood cells cannot be stored for more than 42 days.

Interesting Human Blood Facts 26-30

26. Donated platelets cannot be stored for more than 5 days.

27. Donated blood plasma can be stored for 1 year in frozen condition.

28. Platelets, red blood cells and blood plasma can be separately donated instead of donating blood as a whole. This type of donation is known as Apheresis.

29. Humans can have artificial heart but there is absolutely no substitute for human blood. There is no such thing called artificial blood.

30. Our body has about 0.2 mg of gold. Most of this gold is actually in our blood.

Interesting Human Blood Facts 31-35

31. We find pus kind of disgusting but it is actually nothing but white blood cells that died while defending our body against infections.

32. The only place where blood cannot be found in human body is the cornea (eye) because cornea is capable of directly extracting oxygen from air.

33. Supply of blood in blood vessels located in nose increases when someone catches cold. This happens to keep the nose warm. As a result of this blood vessels dilate and increase mucus production and leads to runny nose.

34. Scientists have come up with a method that can be used to send oxygen directly to blood without using the lungs.

35. Mosquitoes have an uncanny preference to the blood type they suck. They prefer blood group O more than other blood groups.

Interesting Human Blood Facts 36-40

36. 1,200,000 mosquitoes together need to suck out blood once from a human body to drain out entire blood in his or her body.

37. More than 400 gallons of blood are filtered by our kidneys every single day.

38. Nearly 1/4th of total cells in human body are red blood cells. So, the total number of red blood cells in an adult human body at any given point in time is around 20-30 trillion. The total number of white blood cells in an adult human body is between 4,000 and 11,000. Please remember that these numbers are just best estimates based on size and volume of the cells in comparison to total mass of an adult human body.

39. Nearly 2 million red blood cells in an adult human body die every one second.

40. Nearly 2 million red blood cells are produced in bone marrow every one second so that they can replace the dead cells.

Interesting human blood facts 41-45

41. Our heart pumps 1.5 million barrels of blood during our entire lifetime. This is enough blood to completely fill 200 tank cars of train.

42. Every two seconds, someone in this world will need blood.

43. The donated blood is actually sold on market collecting 4.5 billion US dollars a year! That’s a huge industry.

44. Donating blood never reduces a person’s physical energy.

45. The amount of fluid lost when donating blood is actually replaced by our body within a few hours.

Interesting Human Blood Facts 46-50

46. It takes up to 4 weeks to replace the number of red blood cells lost during blood donation.

47. It takes up to 8 weeks to replace the amount of iron lost after blood donation. This is precisely why a person is not allowed to donate blood twice within 8 weeks.

48. On an average, an adult human body (not considering whether male or female) consists of 5 liters of blood which is equivalent to 10 pints of blood.

49. One pint of blood is capable of saving 3 lives.

50. If a person donates blood every 56 days (8 weeks) starting at the age of 17 and stops donating at the age of 79, he or she would donate a total of 46.5 gallons of blood, which is equivalent to 176 liters of blood.

Interesting Human Blood Facts 51-55

51. Someone in the world actually donates blood every 8 minutes.

52. One out of every 10 people entering hospital will need blood.

53. Anywhere between 2 and 25 units or pints of blood is required during brain surgery.

54. Anywhere between 2 and 5 units or pints of blood is required during hip replacement surgery.

55. At least 4 units or pints of blood may be required for cancer treatment.

Interesting Human Blood Facts 56-60

56. People suffering from sickle cell disease need up to 4 pints or units of blood every single month to survive.

57. Victims of severe car accidents need up to 50 pints or units of blood before their conditions normalize.

58. Not everyone willing to donate blood is allowed to do so. People are usually screened for transmittable diseases before they are allowed to donate blood.

59. Patients who suffer from anemia require blood transfusion so that the count of red blood cells in their blood can be increased.

60. Shortage of supply of all blood groups increase during both winter and summer holidays. The two most common blood groups that fall short very often are B and O.

Interesting human blood facts 61-65

61. At the age of 13, a person named James Harrison needed 13 liters of blood for a major surgery. After he turned 18, he started donating blood. It was found that his blood contained a very rare antigen that was capable of curing Rhesus disease. Till date, Harrison has donated blood 1,000 times and is responsible for curing 2,000,000 unborn babies from that disease.

62. Bayer pharmaceutics is possibly one of the most unethical companies in this world. The company once sold blood products that were contaminated with Hepatitis C and HIV. By the time the company learned that the product was contaminated, 10,000 people in US had already contracted HIV. The company did withdraw the products from US market but sold them in Latin American and Asian markets to continue profiting from the products.

63. In Ireland there was a tradition of giving a pint of Guinness to anyone who donated a pint of blood. The pint of Guinness was given to replace the iron the donors lost by donating blood.

64. Saddam Hussein, during the late 90s, commissioned some people to write a Quran using his blood. The Quran was written but it remains a paradox for Muslim leaders. A Quran cannot be written using blood because it is a sin in Islam but the Quran cannot be destroyed either because that too is a sin. That Quran exists but no one knows what to do with it.

65. There is a type of fatal blood disease whose only cure is to donate blood. The disease is known as hemochromatosis, which is actually a genetic mutation where too much iron gets absorbed in gut causing toxic iron buildup in organs.

Interesting Human Blood Facts 66-70

66. George Washington was killed by his doctors. He was actually bled to death. Doctors used the then popular practice of bloodletting to cure his sore throat problem. It was nothing but a method of removing dirty blood. By the time bloodletting treatment was finished, more than half of total blood in Washington’s body had been removed which turned out to be fatal.

67. Blood type is an indicator of a person’s personality – this is what Japanese people believe. Thus, Japanese market is flood with good themed after blood types. Products like books, drinks, condoms etc. with blood-type theme are sold in Japan.

68. Even Facebook’s Japanese version has a drop down option of ‘Blood Type’ for user profiles!

69. Blood can become dark greenish-black in color. This usually happens because of a type of migraine medication.

70. Ancient Egyptians believed that wine was nothing but blood of people who dared to battle against gods. The reason why they believed this is that drinking wine temporarily made people crazy and drove them out of their senses. This is precisely why ancient Egyptian avoided drinking wine.

Interesting Human Blood Facts 71-75

71. Every year, around 1.3 million pints or units of donated blood is wasted because the shelf life of blood is 42 days.

72. Kidneys are actually responsible for regulating the production of red blood cells in human body. Kidneys are responsible for producing erythropoietin hormone (EPO) that binds with the receptors in stem cell walls in bone marrow and after a complex set of events, the DNA of stem cells are transformed into red blood cells.

73. Kidneys will release EPO only when it finds that oxygen levels in blood have gone below normal. In other words, kidneys are responsible for measuring levels of oxygen in blood.

74. People suffering with kidney failure generally become anemic because kidneys fail to produce enough EPO that can stimulate the production of red blood cells in bone marrow. This however never means that all anemic patients have failed kidneys.

75. The first ever successful blood transfusion was not between humans but between dogs and this event took place somewhere in 1660s.

Interesting Human Blood Facts 76-80

76. The first ever blood bank of the world was opened in Chicago in year 1936.

77. William Harvey was the first person to describe blood circulation in 1628.

78. The circumference of earth is 40,000 kilometers or 25,000 miles. If all blood vessels in a human body are placed end to end, they can wrap around our earth nearly 2.5 times!

79. Red blood cells are special cells in our body. They do not have nuclei. Because there is no nucleus in a red blood cell, it cannot multiply through cell division because for a cell to undergo cell division, a nucleus is necessary. Thus, red blood cells simply die out after 120 days.

80. Blood has wonderful staining property. It is because of this property that Native Americans often used blood as paint!

Sources: 1, 2, 3, 4, 5, 6

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