Final answer:
The anterior portion of the nasal cavity near the nostrils, known as the vestibule, is lined with mucous membranes and hair follicles that filter debris and begin the process of conditioning inhaled air.
Step-by-step explanation:
The region of the nasal cavity near the nostrils is commonly referred to as the anterior portion or the vestibule. This area is lined with mucous membranes that serve as a barrier, containing sebaceous glands and hair follicles that help trap and prevent large debris like dirt from entering deeper into the nasal cavity. The vestibule is the nasal cavity opening where inhaled air first begins to be conditioned, undergoing warming and humidification, before passing through the rest of the respiratory tract. The nares, or nostrils, lead into this anterior portion, making it the primary opening for the air we breathe.
The nasal cavity also contains the nasal conchae, curved bony plates that increase the surface area to enhance air warming and humidification. Additionally, the olfactory epithelium, which is responsible for the sense of smell, is located deeper in the nasal cavity. These structures, including the adjacent sinuses and the nasopharynx, work collaboratively to ensure that the air entering our respiratory system is properly processed.