In this video, we're going to talk some more details about chronic inflammation. And so first, we need to recall from some of our previous lesson videos that we already chronic inflammation as a long-term immune response, where symptoms are going to develop slowly and they are going to last a long period of time. For example, several years. Now, unlike acute inflammation, which is characterized by an abundance of neutrophils, chronic inflammation is characterized by an abundance of macrophages, giant cells, and T lymphocytes or T cells. Now recall that giant cells are the fusion of 2 macrophages, and T lymphocytes or T cells are cells that are part of adaptive immunity. Now these macrophages, giant cells, and T lymphocytes can accumulate to form what is known as a granuloma. And so a granulomas or granulomas are really just concentrated groups of cells that are important for retaining or walling off microbes that cannot be easily destroyed.

And so if we take a look at our image down below, notice on the left-hand side we're showing you our map of the lesson on these innate effector actions, and we're specifically focusing on inflammation and chronic inflammation here. And so once again, chronic inflammation is characterized by a long-term immune response. And so notice in this cartoon on the left over here we have a person whose knee is displaying some inflammation through rheumatoid arthritis. And notice that several years later, a long period of time later, this arthritis and inflammation are still occurring. And so this is an example of chronic inflammation, long-term inflammation that can last a long period of time. Now down below what we're showing you is, once again, chronic inflammation and the granulomas that can form during chronic inflammation. And so over here what we have is the Mycobacterium tuberculosis which is the bacteria that causes tuberculosis. And then, we have the image of the macrophage, B cells, and T cells. And what you'll notice is that these granulomas are going to consist of a bunch of immune system cells that are gathering to create a structure to wall off and block and retain the bacteria so that the bacteria are not capable of spreading. And this really only occurs during severe chronic long-term inflammation.

And so here's an image of the granuloma in the lymph node. And so this here concludes our brief lesson on chronic inflammation, as well as granulomas. And we'll be able to get some practice applying these concepts as we move forward, so I'll see you all in our next video.