Final answer:
The nasal cavity is the part of the respiratory system most affected by particles larger than 10 micrometers, where hairs and mucus trap these particles. Further defense is provided by bronchi and bronchioles, which utilize mucus and cilia to prevent particles from reaching the lungs.
Step-by-step explanation:
The part of the respiratory system affected by particles larger than 10 micrometers (mcm) primarily includes the nasal cavity and the upper airways. Particulate matter, such as dust, dirt, viral particles, and bacteria, can cause damage or trigger allergic immune responses. However, the respiratory system is equipped with protective mechanisms: in the nasal cavity, hairs and mucus play a vital role in trapping these large particles to prevent them from reaching the more sensitive parts of the respiratory system, like the lungs.
The air is also warmed and moistened in the nasal cavity to protect delicate lung tissues. If particles bypass the nasal cavity or enter through the mouth, the bronchi and bronchioles offer additional defense with mucus and cilia. The mucus traps particulates while the cilia help in moving trapped particles out of the bronchi and bronchioles back up to the throat to be swallowed.