Topic 3.5
Key Concepts
- The immune system defends the body using three lines of defence: physical barriers (like skin), non-specific immunity (inflammation and phagocytes), and specific immunity (B and T cells).
- Vaccines train the immune system to recognise and fight pathogens without causing illness.
- The body remembers past infections, enabling a faster and stronger response to repeated threats.
Summary
In this unit, we explored how the immune system protects the body through its three lines of defence. The first line blocks most invaders using physical and chemical barriers, while the second line activates a rapid, non-specific response to fight anything that breaches these barriers. The third line provides a targeted, adaptive response, using B and T cells to destroy pathogens and build long-term immunity.
We also discussed how vaccines help prepare the immune system for specific threats, allowing the body to respond faster and more effectively. Finally, we examined how these principles apply to real-world challenges like combating viruses (e.g., COVID-19).
By understanding these processes, we can better appreciate how the immune system works to protect us and how we can support it through vaccination, hygiene, and healthy habits.
Extension Activities
Which type of barrier to pathogens is, in your opinion, the most effective? Explain why.