The skin serves as a barrier to pathogens through the production of __________, which has antimicrobial properties and helps maintain the skin’s pH.

The skin protects against germs by producing antimicrobial peptides, such as defensins, that kill bacteria and fungi. These peptides also help keep the skin slightly acidic, which is a hostile environment for many pathogens. When the skin barrier is intact, the peptides are secreted by skin cells and sweat glands. For example, a tiny amount of defensin released in a cut can neutralize a bacterium that might otherwise cause an infection. This dual action of killing microbes and maintaining low pH makes the skin a powerful natural defense.