Cartilage is a tough, flexible tissue in your body that's softer than bone but firmer than skin or muscle. If you pinch the tip of your nose or bend your ear, you're feeling cartilage at work. It has enough give to bend without breaking, but enough strength to hold its shape.

Your body uses cartilage in several important ways. It cushions the places where bones meet, like in your knees and elbows, acting like shock absorbers that keep bones from grinding against each other when you run or jump. It also gives structure to parts of your body that need to be flexible: your nose, your ears, and the rings that hold your windpipe open so you can breathe.

Unlike bone, cartilage doesn't contain blood vessels, which means it heals very slowly when injured. That's why doctors take cartilage damage seriously, especially in athletes. Sharks have skeletons made entirely of cartilage instead of bone, which makes them lighter and more flexible in the water. Human babies are born with lots of cartilage that gradually turns into bone as they grow, which is one reason babies seem so bendy compared to adults.