Immune System - GCSE Biology Definition

The immune system is the body's defence system that helps protect us from getting sick. It is made up of different cells, tissues, and organs that work together to fight off pathogens, such as bacteria and viruses, which can cause diseases. When these pathogens enter our body, the immune system detects them and sends out signals to white blood cells, which attack and destroy the invaders. It can also remember the pathogens so that if they try to invade again, the immune system can react faster and stronger. This is why vaccinations are important—they help our immune system to recognise certain pathogens without us getting ill. The immune system is essential for keeping us healthy and safe from infections.