Primary Defences

Primary Defences

1. Examples

   • Skin
     • a physical barrier
     • also a chemical barrier
       • sebaceous glands produce oily sebum which waterproofs and has an antibacterial chemical with a low pH to inhibit microbial growth
     • can be penetrated by cuts, insect bites and natural boday openings
   • Mucus membranes
     • these protect body openings eg. mouth, ears, nostrils and genitals
     • most of them secrete mucus to trap pathogens
       • the mucus usually contains an antibacterial chemical to slow the muliplication of the bug
   • Tears
   • Blood clotting

2. their function is to stop the entry of parasites and pathogens

3. block a huge number of microbes daily

4. if the primary defences are penetrated, the first response of the body is phagocytosis