[Voiceover] This slide is of osseous tissue. It's a tissue, the primary tissue, that makes up bones. The current magnification is 100x total magnification. And what we're looking for is again the features of connective tissue and the specialized features of osseous tissue. So when we start looking, one thing that should really jump out are all of these kind of patterns of circles. Now these circular patterns, each one is referred to as an osteon. Now an osteon is the structural unit of osseous tissue or hard bone. So if we zoom in a little bit, we can look at this one osteon, which is right in the center of our field of view. Now in an osteon, you have several features. First off, we need to look at the cells. These little black dots you see kind of forming a ring shape around, each black dot is going to be an osteocyte, which is the cell inside of lacunae, which is a space. Now you cannot differentiate on the slide because the actual stain that's used here fills up lacunae so all you can see is this space that was filled. That space is lacunae with the osteocyte inside at this point. We can also see this very large opening right in the center here. Again, the black color is the dye so this is a space filled with dye. This space is called the central canal or also known as the haversian canal. This is where blood vessels and nerves can run through the bone so it's a big open space. Radiating out from this central canal, all these tiny little cracks, you can see one right here, one's going here, one's there, one's there, what these are doing, these are microscopic cracks that radiate out from where the blood is, the central canal, out to where the living cells are, the osteocytes. So these little tiny cracks allow for diffusion of nutrients and of gases. Now these little tiny cracks, singular, are called canaliculis, or if you're talking about plural, many of them, are canaliculi. So these microscopic cracks radiating around are canaliculi. Another thing you can notice is that these rings of osteocytes and lacunae are kind of stacked, there's one ring, a second ring, a third ring, a fourth ring. Each individual ring, so from here to here, is referred to as lamellae. So you have one ring here, one here, one here. So we have several features that are making this osseous tissue unique. The central canal, osteocytes and lacunae, canaliculi, the tiny cracks, and the rings, the lamellae. And you're saying, well, why is this connective tissue? Well, connective tissue has three things: Cells, we have those, osteocytes, then you have to have fibers, that's found in this extracellular matrix, it's the actual hard part of the bone. The reason it's hard though is not just the fibers, which in this case is a lot of collagen, but they also have mineral deposits and it's that mixture of minerals and fibers that give bone the hardness and the density. So we have our connective tissue, osseous tissue.