immune system

The immune system is the body’s built-in defence team that protects you from disease-causing germs.

• What it is made of: A network of organs, cells, and chemicals—like white blood cells, antibodies, the skin, and organs such as the lymph nodes and spleen.
• What it does: It detects harmful microbes (pathogens), attacks them, and helps remove infected or damaged cells so you can recover.
• Two lines of defence:
  • First line (barriers): Skin, mucus in the nose, tears, and stomach acid act like walls and traps to stop germs from entering.
  • Second line (fighters): White blood cells hunt and destroy germs that get inside, and antibodies can stick to specific germs to help neutralise them.
• Memory is its superpower: After fighting a germ (or after vaccination), the immune system can “remember” it. Next time, it responds faster and stronger, often stopping illness before you feel sick.
• Why people differ: Sleep, nutrition, stress, exercise, and existing health conditions can affect how well the immune system works—so two people in the same place may not fall sick equally often.
• Important nuance: A strong immune system doesn’t mean you never meet germs—it means your body is better at controlling them and preventing serious disease.