Osteocytes residing in lacunae of osteons of healthy compact bone are located quite a distance from the blood vessels in the central canals, yet they are well nourished. How can this be explained?

Video transcript

Welcome back, everyone. Here's our next question. Which of the following cells is found on the surface of bones and regulates the exchange of minerals between bone tissue and the surrounding fluid. A osteocyte B Osteoblast C bone lining cells or D fibroblast. Well, luckily in this one, we have a pretty clear indicator from the name of the cells we're looking for, we're asked for which cells are found on the surface of bones. And the answer is choice C bone lining cells, those are cells that line the surface, particularly of inactive bone. So line so a bone that is not in the process of remodeling and they do regulate the exchange of minerals between bone tissue and the surrounding fluid. Let's look at our other answer. Choices. Choice D can be ruled out pretty easily. Fibroblasts. Fibroblasts are cells that produce connective tissue, not bone. So they do this by secreting collagen. So that one's pretty straightforward to rule out and then choice A osteocyte and B osteoblast. Well, we have the part of the word blast in here, a cell that has the word blast in it is a cell that produces something like we had A fibroblast is involved in producing or making cells or tissues. Uh clast like osteoclasts is a cell involved in breaking down materials. So that's a helpful thing to keep track of things. So, osteoblasts are the cells responsible for bone formation and they do this by synthesizing and secreting the collagen matrix and other proteins that make up bone tissue. So they are not the binding cells but the cells that are right there in the center of things forming new bone osteocyte. In choice A is basically mature bone cells. When an osteo blast becomes surrounded by a matrix and is no longer producing, it becomes an osteocyte. So the osteoblast that's no longer forming new bone becomes an osteocyte, but it's also not lining the surface of the bone, it's there surrounded by that matrix. So again, the cells found on the surface of bones that regulate the exchange of minerals. Choice C bone lining cells. See you in the next video.