96,560 kilometers (60,000 miles). If you could lay them all out in a really straight line they'd go more than two times around the earth.

One thing blood vessels aren't is really straight. They crisscross all over your body. Their job is to carry blood throughout our bodies. There are three main types of blood vessels – arteries, veins, and capillaries.

Arteries are the thickest and most muscular blood vessels. They can contract to help keep moving blood along. Most arteries carry oxygen-rich blood away from your heart to the other parts of the body. The width of your arteries becomes smaller as you follow them away from the heart. Eventually the arteries connect to the tiny capillaries.

Often it’s the little things that are the most important. Capillaries are a perfect example of this. Through them oxygen and food are delivered by the blood to the trillions of cells that make up our bodies. Once the goods are delivered the capillaries help carry away waste products. Eventually, the capillaries connect to the larger veins.

Veins carry blood back toward the heart. They aren’t as thick and muscular as arteries but they do have little valves in them to help prevent blood from flowing backwards.

Comments (1)

hukiworld said:

	Hansel and Gretel I guess Hansel could've used blood vessels to lay on the ground to find his way back when they went into the woods lmfao!
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June 29, 2010 | url
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