You’ve probably heard about veins before, but did you know that there are actually two other types of blood vessels in the circulatory system? Each one plays an important role in keeping your blood flowing and making sure that your heart, lungs, and other organs get the oxygen and nutrients they need.
Another type of blood vessel you should know about arearteries. Arteries carry bloodawayfrom the heart. First stop for this blood is in the lungs, where it picks up oxygen. Arteries carry this oxygenated blood and divide into smaller vessels calledarterioles(‘small arteries’), which ultimately divide into even smaller branches calledcapillaries. Capillaries connect arteries to veins, and exchange oxygenated blood for blood with carbon dioxide in it.Veinstake that waste-rich blood back to the heart, stopping by the lungs again so that the CO2 can be dropped off and expelled from the body.
You might not know that veins contain valves - valves make sure that blood flows in the correct direction, even against the force of gravity. Arteries, on the other hand, don’t need valves - the blood flowing in them is under so much pressure from the heart that it can only flow in one direction!
Here are three fun facts about these amazing little tubes of muscle:
1. Although individual blood vessels are tiny, they’re enormous when put together - if you laid all of a grown adult’s veins, capillaries, and arteries out in a line, they would be over 60,000 miles in length! That’s long enough to go around the worldtwice!
2. Ever had a brain freeze? You can blame it on your blood vessels. When something super cold, like a popsicle, touches the roof of your mouth, your mouth’s blood vessels constrict to try to keep from losing heat, then quickly relax again to keep blood flowing. This rapid response can feel painful for a few minutes while your body adjusts to the temperature change.
3.Every day, your blood vessels transport the equivalent of around 1,800 gallons of blood around your body. Over your lifetime, that adds up to around amillion barrels! That’s a whole lot of blood!