Mechanisms of Defence
- The human body defends itself against disease in many ways
- One example is the skin
- The skin is a structures that make it difficult for pathogens to get into the body
- It covers almost all parts of your body to prevent infection
- If the skin is cut or grazed, blood clots form to seal wounds by forming a scab
- This prevents the entry of pathogens
- On the surface of the skin is a community of micro-organisms called the skin flora
- These bacteria compete with any invading pathogenic bacteria preventing them from becoming established
- The skin is a structures that make it difficult for pathogens to get into the body
- If pathogens enter the body, different defence mechanisms are activated
- For example, through activation of white blood cells
- Different types of white blood cells work to prevent pathogens from reaching areas of the body they can replicate in
- Phagocytes engulf and digest pathogenic cells
- Lymphocytes
- produce antibodies which clump pathogenic cells together so they can’t move as easily, and release chemicals that signal to other cells that they must be destroyed
- produce antitoxins which counteract the toxins produced by bacteria
Phagocyte ingesting a pathogen diagram
Phagocytes engulf pathogens and digest them to prevent them causing harm
