What is phagocytosis and how does it actually work?

Overall, there are three main methods that white blood cells defend against infection that you need to know about for GCSE. The different methods are because there are different white blood cells. The most basic and general way white blood cells defend against infection is by phagocytosis. This word can be broken down to explain what it does - "phag-" means to eat, and "cyt-" refers to a cell. So phagocytosis is eating the cell. That means that the white blood cell, called a macrophage (essentially meaning big eater!), follows the pathogen, whether it's a bacterium or virus or fungus, etc, and then ingests the pathogen by essentially absorbing it. It then digests the pathogen inside it and releases the products. The reason why it's basic and general is because it's non-specific. It doesn't need to find a particular pathogen, it will just ingest any pathogen that's not meant to be in your bloodstream, which means it's fast-acting defence.