One of the main weapons that the cells of the innate immune system have against pathogens is phagocytosis. It allows them to remove these pathogens and prevent them, hopefully, from infecting any cells. Now, there are going to be 3 types of cells that will be performing phagocytosis in the innate immune system. Those are neutrophils which are phagocytes, or cells that perform phagocytosis, that will circulate in the blood and they're going to be attracted to infected tissues by cytokines, those messengers, or those messenger molecules, those chemical signals that will attract cells of the immune system. So, if I jump out of the way here, you can see a neutrophil circulating in the blood, you know, here we have a red blood cell. And it's going to circulate in the blood and look for these cytokines. And it's going to be attracted to them. Go in. Look for those pathogens that you can see here. So, that's a pathogen and it's going to phagocytose them. It's going to eat them up. And you can see what that phagocytosis kind of looks like here. The cell will actually pinch its membrane around the thing it's trying to engulf and basically suck it in in a vesicle. And here in this particular cell, it's actually going to digest what it takes in and break it down like you see there. Now, neutrophils are kind of like the mobile warriors. They're going to go seek and destroy these pathogens but macrophages are more like defenders. They tend to hang out in tissues and organs that will frequently encounter pathogens, and they'll mainly be found around the lymphatic system and especially lymph nodes because, you know, there are going to be a lot of pathogens that cycle through there. And, in addition to macrophages, you'll find dendritic cells in those areas too. And these dendritic cells are also phagocytes except their job is a little different. Gobble up the pathogen they find like, for example, the macrophages. Its job is just to gobble up any pathogen it finds; so like here's a bacteria it's going to gobble it up, remove it. Dendritic cells are there to actually take what they phagocytose and use it to stimulate the adaptive immune system. So, their job is super important because they're going to bridge the innate immune system and the adaptive immune system and they're going to help trigger an adaptive immune response. So, these phagocytes are not the only innate immune responses our body has, some other tactics they can use. You might not think of it because, you know, we tend not to deal with this in our day-to-day anymore but, you know, we used to have to worry about parasites much more often. We actually have these immune cells called eosinophils that are there to defend against multicellular parasites. And we also have some defenses against viruses. There are these cells called natural killer cells, cell death. And, if I jump out of the way here, you