Our example wants us to identify which structures and cells are associated with compact bone and which are associated with spongy bone. And we have a table here. We have a list on the left-hand column of vocabulary, not all the vocabulary we've learned, but a fair amount. We have a column for compact bone and a column for spongy bone. I'm going to go through.
I'm just going to give a check if it's in that type of bone, and I'll leave it blank if it isn't. Now we also over here, we have these diagrams that we've seen before. We have a diagram showing our structure of compact bone on the top, and we have a diagram showing the structure of spongy bone on the bottom, just to remind us. Alright. So first up, we have the osteoblast.
So do you find osteoblasts in compact bone or spongy bone? Well, osteoblasts are those bone-building cells, and they build the matrix for any bone. So they are going to be in both compact bone, I'll give the green check there, as well as spongy bone. Next up, we have the perforating canals.
Where do you find them? Well, if we look over at our diagram here of the compact bone, remember, the perforating canals run perpendicular to the central canals. They're connecting the central canals with the blood supply and supplying them with nerves as well. So that's going to be in the compact bone because that's where you find the central canals. The spongy bone has all spaces through it.
You don't need canals for blood vessels to go through. There's just space in the spongy bone where the blood vessels can be. Next, we have the endosteum. Think endosteum in compact bone or spongy bone.
Endosteum, remember, is that very thin layer of osteoprogenitor cells that's on the inside of the bone. Well, it is definitely in spongy bone. So I'm going to give a check there because every single trabecula, all those trabeculae, are wrapped with that endosteum. Now, in compact bone, it's going to just be along the very edge of the compact bone.
It will be in the medullary cavity there along the edge. So I am going to give it a check for compact bone, but I just do want to stress, maybe I'll put the check-in spongy bone in a circle just because it's definitely more associated with the spongy bone, but it is associated with the inside of that compact bone as well. Next, we have the osteons.
The osteon, compact bone, or spongy bone? Well, we said that the osteon is the functional unit of compact bone, so I'm definitely giving the check there. And we said it's like you see the different tree trunks when you look at the cross-section of compact bone. You see all these different circles on the compact bone. We said in spongy bone, there is no osteon.
So we're going to leave that one blank. Next, we have the trabeculae. So trabeculae, compact or spongy bone? Remember, trabeculae are the struts in spongy bone, so we'll find them in spongy bone. Compact bone doesn't have any struts. It's all solid, so we're going to leave that one blank. Next, we have the osteocytes. So osteocytes, compact or spongy bone.
Remember, osteocytes are the mature bone cells, and they are living inside the matrix. They're living inside the matrix of compact bone and in the trabeculae in the spongy bone. So I'm going to give a green check to both of them. And finally, we have the canaliculi. Canaliculi, you find them in compact bone or spongy bone.
Remember, those are the smallest little spaces in the bone that those osteocytes can connect with each other. So because the osteocytes, living in their lacunae, are in both types of bone, you need the canaliculi in both types of bone as well. With that, we have practice problems to follow. Give them a try.