How Does The Circulatory System Part 2: Blood Vessels Work?

The circulatory system uses blood vessels like roads for cars to travel around your body.

Imagine your blood is a car, and your blood vessels are the roads it drives on. There are big highways called arteries, which carry blood from your heart to your arms and legs. Then there are smaller streets called veins, which bring the blood back to your heart. In between, tiny little paths called capillaries let the blood talk to the cells in your body, like a playground where blood gives candies (nutrients) and takes away toys (waste).

Your blood vessels are like balloons that can stretch when you need more blood, or shrink when you don’t. For example, when you run, your legs get more blood because the arteries there stretch wide open, it's like a highway turning into a superhighway! When you rest, they go back to normal size.

Sometimes, if the roads (blood vessels) get clogged with gunk (like cholesterol), it’s harder for the cars (blood) to travel, and that can make your heart work extra hard.