Question: What is the function of the immune system?

Max Jamilly answered on 9 Mar 2018:

Hey Nico. That’s a big question – but an important one! Without the immune system, the body would have no way to defend itself. Think of the body like a city. Invaders may attack the city – these are infectious things like viruses and bacteria (known as pathogens). But problems can come from within the city, too – this includes cancer, where cells go mad and start dividing out of control. Like a police force, the immune system is constantly patrolling the body, looking for damage or infection. If it finds anything, it releases SOS signals into the blood to attract even more immune cells – especially white blood cells. These find, kill and eat any pathogens and then make a record of what they looked like so they can defend against them even quicker next time. The immune system is REALLY important!