Lymph nodes are little bean shaped structures filled with the cells of the immune system and dotted around the body. Pathogens from skin injuries or that enter the body in other ways are passed to a lymph node and the cells here can respond. They are major parts of the immune system but metastatic cancer cells may also pass here, get stuck and continue to proliferate. This is important anatomy then, so let's quickly talk about it in around 5 minutes of podcast world time.