65 Fun Facts About The Circulatory System: What Do You Need To Know?

The circulatory system is the fascinating system that keeps blood moving around round the body.

The heart and all blood vessels such as veins and arteries make up the circulatory system. It’s also known as the cardiovascular system.

The body’s circulatory system is primarily responsible for transporting materials across the entire body. It successfully delivers nutrients, water, and oxygen to billions and billions of body cells and transports away wastes such as carbon dioxide from production with the body's cells. In essence, it is an incredible and intricate highway that travels through your entire body connecting all your body cells. Take a look at our top facts about the circulatory system here and if you’re updating your knowledge on incredible facts about the human body, why not check our fun facts about the respiratory system and dental facts?

Let’s take a look at facts about how the circulatory system works and what you need to know.

1. The circulatory system consists of five main parts, blood, the heart, blood vessels, arteries, capillaries and veins.

2. Five different types of blood vessels make up the human circulatory system, and they are the arteries, arterioles, capillaries, venules and veins.

3. Blood travels away from the left side of the heart.

4. Arteries are the variety of blood vessels which carry blood away from the heart.

5. Veins carry deoxygenated blood (blood without oxygen) in the direction towards the heart.

6. When it comes to facts about the heart, interestingly veins get bigger as they go towards the heart.

7. It takes 20 seconds for blood to circulate the entire human body. Oxygenated blood leaves the aorta of the heart at the speed of 1 mile an hour.

8. The smallest veins in the circulatory system are called venules.

9. Between arteries and veins are capillaries. These vessels are relatively thin, hence the name which originates from the Latin word capillus meaning “hair".

10. The average adult human has between 10-12 pints of blood travelling through their circulatory system.

11. Three circulatory processes occur within the body at the same time: – Systemic Circulation, Pulmonary Circulation and Coronary Circulation.

12. Bone marrow is a thick, dense spongy kind of jelly inside your bones. It is essential as it makes all kinds of blood cells needed in your circulatory system.

13. There are two varieties of bone marrow, yellow and red. Both types contain many capillaries and blood vessels.

14. When a baby is born, their bone marrow is completely red. As they grow older, more and more of the bone marrow changes to the yellow type.

15. Cardiac output (Q) is the name for the volume of blood pumped from the heart per minute.

16. Every part of the body receives blood, except the eyes.

17. The majority of veins have valves to stop blood from flowing backwards around the circulatory system.

18. When there is a problem with valves not working correctly and blood going backwards, this is called regurgitation, and your heart has to work much harder to push blood the right way around the circulatory system.

19. If there is a problem with the valve not opening and closing properly, this is called stenosis, the heart also has to work much harder to push blood through these valves.

What exactly is blood? let’s take a look at these facts about blood as well as facts about the cardiovascular system.

20. Blood is a liquid tissue: fluid makes up more than half; plasma, white and red blood cells make up the rest.

21. 7% of your entire body weight is blood.

22. Plasma is the light-yellow liquid part of your blood; it holds all of your blood cells.

23. After the blood gets oxygen in the lungs, it is called oxygen-rich blood, it then travels to the heart and throughout the body.

24. Red blood cells collect oxygen from your lungs and deliver it to tissues throughout your body. They also transport carbon dioxide back to your lungs.

25. There are over 5 million red blood cells within a single droplet of blood

26. 120 days is approximately the average life span of a red blood cell.

27. Red blood cells make up almost 50% of the blood in the human body.

28. Within the circulatory system, white blood cells are vital as these are the ones that fight against infections.

29. White blood cells have a different lifespan to red blood cells; they can live up to years.

30. Blood pressure is the measure of the force of blood against the wall of an artery.

31. Blood contains important platelets that are essential for clotting the blood. If a blood vessel is damaged, a clot forms to stop blood from escaping.

32. The blood of mammals is red in color due to a substance called hemoglobin.

33. Throughout an average lifetime, your heart beats over 2.5 billion times.

34. White blood cells travel around the circulatory system in blood vessels to fight germs, infections, viruses, and illnesses in the body.

35. There are four main blood types; these are A, B, O, and AB. Each blood type is slightly different and has different antibodies and antigens.

36. A pacemaker is a small device which is inserted into the body to send electronic signals to the heart, it’s used when someone has abnormal heart rhythms. Pacemakers help blood flow correctly around the circulatory system.

37. There are enough blood vessels in the human body to wrap around the Earth a staggering 2.5 times.

The heart is at the center of the circulatory system and it plays a very important role. See how many of these interesting facts about the heart you can memorize.

38. The average size of a heart is the same size as a fist.

39. When it comes to the shape, contrary to popular belief the human heart is not heart-shaped.

40. Electrical signals within the heart prompt the heart to beat.

41. Around the heart is a special sack called the pericardium.

42. 115 thousand beats are the number the average heart beats a day.

43. 60-100 is the average number of heartbeats per minute.

44.  An average heart pumps approximately four tablespoons of blood per beat.

45.  A baby's heart is twice as fast as an adult's, a newborn baby’s heartbeat is around 100-150 beats per minute

46. In 1967, Christiaan Barnard and his team performed the first successful heart transplant.

47. The heart is situated inside your chest and protected by your ribcage.

48. Your left lung is smaller than your right lung, in order to fit in your heart.

49. The study of information about the heart and its various conditions is known as cardiology.

50. Even when not connected to the body, the heart can continue to beat, this is because it has its own electrical signals.

51. When it comes to cool facts about the heart, the beating sound you hear your heart make is caused by the opening and closing of its valves.

52. The heart is an exceptionally powerful muscle that pumps the blood around your body, it is divided into four chambers.

53. The ventricles are the two chambers at the bottom of the heart. The heart has a ventricle on the left and a ventricle on the right side. Their role is to push out the blood throughout the body and lungs.

54. The Latin meaning of the word ventricle is “little belly”.

55. The right atrium is where blood enters into the heart.

56. The Latin meaning of the word atrium is “entrance hall”.

When it comes to facts for a healthy heart, it’s very important to get enough exercise, eat a well-balanced and nutritious diet to keep your heart and the rest of your circulatory system healthy. There are many ways you can look after your circulatory system and take care of your heart. Here’s our top cardiovascular facts.

57. To keep your system healthy, avoid both trans-fats and saturated fats, these are often found in ready-made processed foods and fast foods.

58. Vitamin D is one of the top vitamins which promotes a healthy circulatory system and keeps blood pumping through the body.

59. Circulatory diseases are classified into cardiovascular diseases (affecting the cardiovascular system) and lymphatic diseases (affecting the lymphatic system).

There’s a whole host of unusual facts when it comes to the circulatory system. Let’s take a look here, from Ancient Egyptian beliefs to how much blood is pumped around your body each day, there are so many interesting facts about the circulatory system.

60. Physicians followed the wrong models of the circulatory system for thousands of years. In 1628, the English physician William Harvey first correctly documented the circulatory system.

61. An impressive 2000 gallons of blood are pumped around the body each day.

62. The Ebers Papyrus, an Egyptian medical document dating to the 16th century B.C, is where the earliest identified writings on the circulatory system appear.

63. The ancient Egyptians also believed the heart, rather than the brain, was the source of emotions, wisdom and memory, among other things. This is where the phrase follow your heart comes from.

64. Physiologist Willem Einthoven invented the electrocardiograph in 1903, this device measures the electric current which flows through the heart.

65. When laid out in a straight line, all the blood vessels in the circulatory system would come to around 60 000 miles in length.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for fun facts about the circulatory system then why not take a look at stroke facts, or for something different these gross facts for kids?