In this video, we're going to focus on the study of tissues. And so the term histology is actually a term that means the study of tissues. More specifically, the term histology can be defined as the scientific study of tissue structure and function. And so, this is going to include studying the shape, size, and arrangement of the overall tissue, but also of the individual cells within the tissue. And it's also going to include studying the ECM or the extracellular matrix.
Which recall from our last lesson video refers to the surrounding material immediately outside of the cells. Now, what's really interesting to keep in mind is that when tissues are prepared for microscopy, generally, those tissues are going to appear transparent or clear under a microscope before being stained with dyes. And so that's exactly what this illustration down below is trying to emphasize. And so notice on the far left over here we're showing you a glass slide with a little bit of tissue sample on it. And if we zoom into that tissue sample as you see right here, you'll notice that initially the tissue is going to be unstained and appear transparent or clear under the microscope.
And so that's going to make it very difficult to study the tissue because the poor contrast makes it difficult to visualize the structures. However, if we add a little bit of dye to our tissue, you'll notice that we can get some stained tissue. And notice that the stained tissue over here on the right is going to be a lot easier to study, a lot easier to visualize the structures because the contrast is significantly improved. And so that makes it a lot easier for the scientists over here to study the tissue. Now moving forward throughout our course, we're going to be showing you a lot of different micrographs or images of tissues under the microscope.
And what you'll notice is that many of those micrographs, or most of them, are going to be, stained. And so that's something important to keep in mind as we move forward in our course. And also, by switching the type of dye that's being used, you can change the color of the staining. And so, here what we have is some kind of pinkish staining, but if you were to use a different type of dye, you could get a bluish staining or a different colored staining. And so this here concludes our brief lesson here on the study of tissues and histology, and we'll be able to get some practice applying some of these concepts in our next video.
So I'll see you all there.