Wikijunior:Biology/Systems/Skeletal System

The Skeletal System
The Skeletal System is made of all of the bones in the body. It protects the reproductive organs, and vital organs like the heart, lungs, and brain, and is a place for muscles to attach. Bones are a very important part of the human body. Without them, we would simply collapse, and be very unstable. They support all of our tissue and muscles, and they are very difficult to break.

The inside of the bones is called the bone marrow. This is where most blood cells are made.

Humans are born with about 300 bones. During childhood, some of these bones fuse together, so that an adult human has a little more than 200 bones.