This example tells me that spongy bone and compact bone are sometimes compared to scaffolding in a brick or concrete wall, and it wants me to explain that analogy. So let's take a look. Alright. Over here on the left, we have scaffolding, and we have a little picture of scaffolding, and it has all these bars or pipes that are connected in different directions. It has a little ladder going up too.
But all these bars and pipes, they're individually quite strong, but when you connect them in all these different ways, you can create a structure that together is incredibly stable and strong, stronger than any one pipe or bar could be on its own. And yet, most of the structure is empty space. That reminds me a lot of spongy bone. Spongy bone, we said, are these bony struts that are pointed in all different directions and connected to each other with space in between them. Together, they create this quite rigid and quite strong structure even though most of the space is filled with marrow.
So my reasoning is that both of them are struts surrounding space. Now we can compare that to this brick wall over here, and this brick wall shows a little picture of some bricks. And brick wall is hard. It is heavy. It is solid.
That reminds me a lot of compact bone. Compact bone is all those things. It's really hard. It's solid. Now technically, there's microscopic space in there, and we're going to learn all about those microscopic spaces in future videos.
But compared to spongy bone, it's much, much more solid, which also makes it heavier. But because it's heavy and hard, that's why it's on the outside of the bone, protecting the scaffolding, the spongy bone on the inside that's a little bit more delicate. So for my reasoning, I'm just going to say those things. It is solid. It's hard.
It's heavy. Have to spell 'heavy' correctly, though. Alright. So we're going to rely on these two analogies a little more going forward, so keep them in mind. For now, there are a couple more problems to solve.
Give them a try.