The layer of defense that prevents foreign microbes from entering the body from outside is called the first layer of defense. It is a non-specific defense layer.
- Skin: Sweat and oil of the skin acts as poison for bacteria. Prevents the growth of sweat and acid bacteria on the skin. The skin’s lysozyme enzyme destroys germs.
- Hair: The hair inside the nose prevents dust and germs from entering.
- Cerumen: Cerumen is a waxy substance known as ear wax. It is secreted from ceruminous glands. It resists bacteria, fungi and insects.
- Cilia: Trachea contains mucus and cilia. It breaks down the germs and expels them out of the body as a sneeze-cough-spit.
- Tears and saliva: Tears and saliva contain lysozyme and histatin. These chemicals destroy bacteria.
- Alimentary acid: Hydrochloric acid and proteolytic acid secreted from the stomach destroy food microbes.
- Fecal and genital acid: Bacteria present in the vagina produce lactic acid. This lactic acid inhibits the growth of other bacteria.
- Microbiome: Friendly microorganisms that live in the body help destroy disease-causing microbes.
- Excretion and Vomiting: Numerous germs are released from the body through excrement and vomiting.