Describe the non-specific, innate defense systems the human body employs to block the entry of external pathogens.
Explain the barrier function of the skin and its production of antimicrobial secretions.
Describe the respiratory defenses, including the trapping of particles by the nose and the secretion of mucus moved by cilia in the trachea and bronchi.
Understand the role of highly acidic stomach acid in effectively destroying the majority of pathogens ingested via the mouth.
