5.4 Physical, chemical and microbiota barriers

physical barriers

innate barriers that act to prevent the entry of pathogens into the body

chemical barriers

innate barriers that use enzymes to kill pathogens and prevent invasion into a host

microbiological barriers

innate barriers involving normal flora in the body

mucous membranes

cellular linings of the inner spaces within the airways, the gut and urogenital tract

lysozyme

an enzyme present in body secretions such as saliva and tears that helps in the first line of defence