Goal of 1st line of defense: to prevent pathogen from entering body
There are physical and chemical barriers where all exposed body entrances would be. Ex. Skin, mouth, eyes, nostrils.
-The skin: composed of tough dead cells that are constantly shedding- physical barrier bc it prevents pathogen from latching on. Skin also contains sweat and oil glands that secrete acids and oils that prevent the growth of pathogens- chemical barrier. Also, sweat contains lysozyme.
Saliva and tears: protect the mouth and the eyes from pathogen invasion. Saliva and tears contain lysozyme.
Nostrils, digestive + respiratory tracts lined with another barrier: mucous.
