Fun Facts about Blood Vessels and Cool Activities for Kids

Did you know that you have 60,000 miles of blood vessels? These important tubes carry blood all around your body from head to toe. Get ready to learn many more fun facts about blood vessels and try cool activities, too!

3 types of blood vessels - artery, vein, capillary

Basic facts about blood vessels

Your amazing body has 3 types of blood vessels: arteries, veins, and capillaries.

  • ARTERIES are the thickest type of blood vessel. These vessels carry blood from the heart to other parts of the body. Because arteries have lots of fresh oxygen, they are usually shown as red squiggly lines in human body diagrams.
  • VEINS are slightly thinner than arteries. These vessels carry blood from parts of the body back to the heart. Because veins have less oxygen, they are usually shown as blue squiggly lines on human body diagrams.
  • CAPILLARIES are the tiniest blood vessels with very thin walls. Because these vessels connect arteries and veins, they are usually shown as purple squiggly lines on human body diagrams.

Fun facts about blood vessels for kids

Here are some interesting blood vessel facts that might surprise you and your friends!

  • Thanks to your pumping heart, blood is constantly flowing through your body, even when you’re sleeping or doing a headstand.
  • Although veins look blue through your skin and in anatomy diagrams, the blood inside is actually dark red. It’s an optical illusion from the way light reflects off of your skin.
  • Healthy blood in arteries are bright red thanks to a special protein called hemoglobin that carries oxygen around your body.
  • The aorta is the largest artery in the body, because it’s directly connected to the heart.
  • The vena cava is the largest vein in the body, because it’s directly connected to the heart.
  • Most of your circulatory system is made up of capillaries, even though they are the smallest type of blood vessel!

Blood vessels coloring page for kids

Hands-on activities can help kids remember the 3 different types of vessels, and this coloring page is a fun and easy activity!

Color the artery red, color the vein blue, and then color the center of the capillaries purple. If you’re not sure what colors to use, check out the picture at the top of this article.

“Fill the capillaries” activity template

This template can also be used for the “Fill the Capillaries” activity on pages 80 to 81 in the Human Body Learning Lab book! Have you tried this fun experiment yet? You might discover that it works best with watercolor paper. Watercolor paper is thick and prevents water and paint from bleeding through the other side.

Please complete the form below to sign up for updates and download this free printable template. The printable should appear instantly when you hit “submit”.

Human Body Learning Lab Fill the Capillaries

Human Body Learning Lab anatomy book for kids

If you think blood vessels are cool, you’ll love learning more about the amazing human body!

Human Body Learning Lab is filled with kid-friendly science facts, memorable experiments, diverse realistic images, and practical health tips.

In addition to the circulatory system, the Human Body Learning Lab book has cool information about all major organ systems.