 Lymphocytes are second most abundant white blood cell and their entire job is about acquired immunity. And so let's take a second with that. Acquired immunity. So what is acquired immunity? You have two branches of your immune system. You have the branch that totally responds to anything and then you have a very specific branch that responds to a very specific guy and lymphocytes facilitate this. What that means is that the cold virus that you get infected with at this time of the year, your body has a general response to that bad guy, but then your body also generates very specific cells, and lymphocytes that match with that specific cold virus so that if you ever get exposed to it again, you can tackle the bad guy and not get sick at all. Doesn't always work with the cold virus because actually you're being infected with a whole new cold virus every season. Oh, thanks. I don't know how long these guys live, but let's draw a picture of them. Like they've got their little circle cell because you know it's a cell, and then they have a big, round, round, moony-looking nucleus. And look at the comparison. Like all my nuclei are kind of funky and lymphocytes have a big nucleus, which we probably could do some work and figure out how that was related to its function, which might be kind of fun. Lymphocytes come in two flavors. We have B cells. Does this sound familiar? And T cells. And we'll talk about them and their specific jobs very specifically in O physio. There was something else I wanted to tell you about basophils. Everybody stays in the circulation except for monocytes, which become macrophages. And basophils actually migrate into the tissues as well, and they become mast cells. And I just want to make sure that we're cool with that. This might be, if you look at it, you know how long do they live. Well, who knows? Because they actually migrate into... Oh, no, it wasn't the lymphocytes. It was these guys, but we did know how long they lived. Ignore what I just said because I knew what I was saying, but I was saying something different than I thought I was saying, okay, that's a perfect time to say, let's call it good. You've got everything you need about blood and the next time I see you, we'll be talking about the boom, boom, boom, boom heart and how much I love you. Okay, bye-bye now.