A spoken monologue (YouTube clip) describing bone as a dynamic, cellular 'machinery' rather than inert hard material. The speaker likens exploring bone to flying through a maze of canals that house vessels and nerves, highlights the surface-lined canals where bone cells activate, and explains that osteocyte dendrite damage (from microcracks) leads to apoptosis and release of unknown signals that trigger repair.
Chapters
When bone is built, and bone is built by a machine, it's built by what I refer to, anyway, I like to refer to as a cellular machinery. Although people think of bone as, like, some hard stuff, I think it's the wrong way to think about bone. Bone is very complex structure that is made of these crystals. And if you could get a tiny space machine. And so you remember that movie, I can't remember the name of it, where they got shrunk. The guys got shrunk down and they were then injected into a vein. Fantastic Voyage, I think it was called 20 years ago, probably. Yeah, yeah. Anyway, so if you could get a tiny airplane, you could fly into the bone. You could fly into one of the canals, just like the many freeways in the Los Angeles downtown area, and you could fly around these corridors and canals of bone that contain vessels and nerves, and then they branch off to the left and the right. And so this maze of or myriad of canals that form the canals inside cortical bone. And it's called compact bone, but it's not really compact at all. It's just compact. When you look at it from an aeroplane down, it really has all of these canals. And these canals are made of surfaces. They have a surface, and on the surfaces, this is where the action is. And the cells of bone that line those surfaces can become activated. So that when there's a tiny crack within the matrix of the bone itself and there's damage, that crack actually tears the nervous system of bone, which consists of osteocytes with their dendrites, with their tentacles. It's like the nervous system in the brain. These dendrites, once they're torn, they kill, they knock off the little osteocyte cells that undergo death by apoptosis. This is a very fashionable way to turn die anyway, so necrosis is out, apoptosis is in. In the 21st century, and these cells die. When they die, they send signals, and we don't quite know what those signals are yet.
