Final answer:
Secondary invaders of the respiratory tract require virulence factors, the ability to survive within host cells, and impairment of the mucociliary escalator
Step-by-step explanation:
Secondary invaders of the respiratory tract are pathogens that can cause infections in the respiratory system. In order to establish an infection, these secondary invaders must have certain requirements:
- Virulence factors: Pathogens produce various virulence factors that help them overcome the immune defenses of the respiratory tissues. Examples include adhesins that help the pathogens attach to host epithelial cells, polysaccharide capsules that allow them to evade phagocytosis, and exotoxins that damage respiratory cells.
- Ability to survive: Some pathogens have the ability to survive within host cells, enabling them to evade the immune system and multiply within the body.
- Impairment of mucociliary escalator: Once an infection is established, it can impair the mucociliary escalator, which is the system responsible for clearing mucus and trapped particles from the respiratory tract. Impairment of this system makes it easier for the pathogens to multiply and spread.