Barriers to disease

The body has a number of barriers to prevent pathogens getting inside it. They can be described as “pathogen stoppers”.

To stop or prevent the spread of infection through a mammals body it produces barriers that kills or combats these microorganisms

The path of gin (pathogen) stopped at the Great Barrier Reef (barrier).

Mechanical barriers

These are physical barriers to pathogens, e.g. nostril hairs, skin, and scabs that form on wounds.

Hair, skin and scabbed wounds are all physical barriers that animals use to combat infection

The mechanic (mechanical barriers) fended off pathogens with his skin, nasal hair and scabs.

These include acid in the stomach, sticky mucus in the lungs and chemicals in tears, which kill or block the progress of pathogens.

Stomach acid, chemicals in tears and thick slimy liquid in lungs are all defenses to prevent infection in the body

The chemist (chemical barriers) killed off pathogens, brought into her shop by customers, with mucus, tears and stomach acid.

Slimy substance secreted by animals for lubrication and protection against invading pollutants and organisms.

Mucus is a slimy substance that is secreted by animals for lubrication and protection against pollutants

A moo cusses (mucus) because it’s stepped into a pool of slime which stops everything getting through the gateway.