Defence and Prevention

 

There are two main lines of defence in the human body:

1. Non-specific → stops pathogens entering  

2. Immune system → destroys pathogens inside

 

1. Non-Specific Defences (Physical & Chemical Barriers)  

 

 

 

 

 

 

 

 

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2. Immune System — White Blood Cells Attack  

 

White blood cells in the immune system have the following 3 functions:

 

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Vaccines

 

How does a vaccine work? 

1. Inject dead/inactive pathogen  

2. This triggers antibody production  

3. The body then remembers the pathogen → this leads to a fast response if the real pathogen returns  

 

The goal is to reach herd immunity. This is where most people are vaccinated against the disease leading to its prevalence decreasing which protects the vulnerable.

 

Antibiotics and Painkillers

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What are the issues with antibiotics?

1. Antibiotic Resistance → bacteria evolve (e.g., MRSA)  

• This is why it's important for people to finish their course of antibiotics

• It prevents bacteria surviving and evolving to become resistance

    2. Doesn’t work on viruses (flu, colds) - they hide in our cells and cannot be easily targeted