So now that we've covered the granulocytes in our previous lesson videos, including the neutrophils, eosinophils, and basophils, in this video, we're going to focus on the agranulocytes. Recall that the agranulocytes are leukocytes or white blood cells with cytoplasmic granules that are not visible or easily visualized under a light microscope after staining. The agranulocytes include monocytes and lymphocytes. Moving forward in our course, we're going to talk more details about each of these different types of agranulocytes. Monocytes are cells that circulate in the bloodstream and can develop into either macrophages or dendritic cells. We'll talk more about macrophages and dendritic cells as we move forward in our course. The lymphocytes include B cells and T cells, and these cells are specifically involved in adaptive immunity. Once again, moving forward in our course, we'll be able to do a deeper dive on immunity and talk about many of its aspects, including adaptive immunity. But here we're reminding you that this will be covered in later videos, and for now, we're focusing on some fundamentals that you should be aware of when it comes to these agranulocytes.

Let's take a look at our image down below. This image is showing us the leukocytes, or white blood cells, which can be broadly categorized into these two major groups: the granulocytes, which we covered in our previous lesson videos, and the agranulocytes, which we are covering now. In granulocytes, you can clearly see those cytoplasmic granules within the cells, those little dots. With the agranulocytes, notice that you don't see those cytoplasmic granules inside those cells. The agranulocytes include monocytes, which are shown in the image here. Recall that these monocytes circulate in the blood and can differentiate into either macrophages or dendritic cells. We'll talk about these cells in more detail moving forward. The agranulocytes also include lymphocytes. The lymphocytes include B cells and T cells. These T cells and B cells are involved in adaptive immunity, which we'll cover in more detail later in our course. As you can see here in this image, the lymphocytes also include NK cells, these natural killer cells. These cells are considered lymphocytes but play a role in innate immunity, not adaptive immunity. We'll get to talk more details about these lymphocytes later in our course as we move forward. But for now, this here concludes our brief lesson on agranulocytes, and I'll see you all in our next video.