Non-Specific Defences Against Pathogens

Non-Specific defences are rapid and prevent pathogens from gaining access to the body.
Non-Specific Defences are the same for all pathogens
Pathogens can enter through openings.
- Like the digestive system or the breathing system
- So they are lined with protective layer called mucous membrane
  - Secrete mucus which traps microorganisms
These microorganisms can then be destroyed by white blood cells called phagocytes.
Mucus contains the enzyme lysozyme which destroys bacteria by digesting the bacterial cell wall.

Sometimes pathogens invade the body through openings such as mouth or nose.
- In this case the body tries to expel the pathogen
  - These are called expulsive reflexes
    - Include sneezing, coughing, vomiting or diarrhoea
If skin is damaged pathogens can enter through the cut
- The body responds to try to seal the damaged area before a large number of the pathogens can enter.
  - This process is called blood clotting

Skin

Provide a protective layer for the majority of the body surfaces.
Consists of many layers of cells including the surface ayer of dead cells.
- Makes the skin difficult for the pathogens to penetrate.
Surface of the skin is covered with oily sebum produced by sebaceous glands
- Forms a slightly acidic layer which can prevent the growth of harmful bacteria.
Healthy skin is also covered in unharmed microorganisms which reduce the growth of pathogens by competing for resources.

Contain lysozyme where it helps to prevent pathogens from entering via the eyes.