Final answer:
The nasal passages, including the hairs, mucous linings, and turbinates, function to filter, warm, and moisten incoming air, as well as trap debris and protect against bacterial infection.
Step-by-step explanation:
The nasal hairs, convoluted passages, and mucous lining of the nasal turbinates play key roles in filtering, warming, and humidifying the air we breathe.
The nares and anterior portion of the nasal cavities are lined with mucous membranes that contain sebaceous glands and hair follicles, which help to block the ingress of large particles like dirt. Deeper within, the olfactory epithelium is essential for odor detection. The nose and nasal cavity are designed with intricacies like nasal conchae - curved bony plates that serve to disrupt airflow, increasing the time air spends in the nasal cavity to get warmed and filtered. This environment is maintained by the cilia and goblet cells within the pseudostratified ciliated columnar epithelium, which trap debris and move mucus towards the throat to be swallowed. The respiratory epithelium also contains immune cells and secretes lysozyme and defensins to protect against bacteria. Moreover, the nearby paranasal sinuses contribute to the air-warming process and reduce the weight of the skull.