Original: It is a viscous colloid containing antiseptic enzymes (such as lysozyme) and immunoglobulins that serves to protect epithelial cells in the respiratory, gastrointestinal, urogenital, visual, and auditory systems in mammals; the epidermis in amphibians; and the gills in fish.
Simplified: It is a viscous colloid that contains antiseptic enzymes (such as lysozyme) and immunoglobulins that serves to protect epithelial cells in the respiratory,gastrointestinal, urogenital, visual, and auditory systems in mammals; the epidermis in amphibians; and the gills in fish.