The video tutorial explains the structure of bones, starting with the hard outer layer called the cortex, which is mainly composed of minerals. It then describes the inner part of the bone, known as the medulla, which consists of a spongy tissue called trabecular bone that is less dense than the outer layer. The ends of the bones, referred to as the epiphyses, and the thin layer surrounding the bone, called the periosteum, are also discussed. Finally, the video defines a joint as the point where two bones meet.

What new insight or understanding did you gain from this video?