For example, if a bacterial cell actually infects our body, then the next time that same type of cell infects our body, it's the acquired immune system that is responsible for initiating the response that recognizes that specific type of bacterial cell and kills off that bacterial cell. So, this is very specific to the type of cells, the type of pathogens it actually attacks. While this type of system does not actually discriminate, it attacks all different types of pathogens equally. So, let's begin by discussing our innate Immunity and the different components that make up our innate Immunity. And let's begin with the physical barrier our skin. So, our skin is the largest organ of our body, and one of the more important functions of our skin is to actually physically protect our body from different types of pathogens for example, UV radiation, as well as bacterial cells and viruses.