It's easy to take bones for granted and ignore them until you break one or are diagnosed with bone-thinning in old age.

In fact, you may not really consider your bones a resource that needs lifelong protection and nurturing.

But guess what? There are a few surprises lurking inside your bones, and youthful habits can even affect bones in old age. Read on to find out more about this living -- yes, they're alive! -- tissue.

PHOTO GALLERY 14 Facts About Healthy Bones