And what that does is dilates our blood vessels and it brings specialized phagocytic immune cells known as macrophages, to the site of infection. So this is what a macrophage actually looks like. So, we have different types of organelles, for example, a nucleus. And we also have these digestive lysosomes, these tiny vesicles that carry digestive enzymes as well as an acidic environment. Now, what the macrophage does is it engulfs our pathogen, in this case our bacteria, and it creates this vacuole within which we have that bacterial cell. And some of these lysosomes fuse with this stagosome.