Nose

The nose is a complex biological structure forming the entry point into the upper respiratory tract. Structurally, it encompasses external cartilaginous and bony supports, which guide the passage of air, and internal nasal passages lined with specialized mucous membranes. Its primary functions include the conditioning of inhaled air; the nasal passages warm, humidify, and filter airborne particles before they reach the lungs. Furthermore, the tissue lining the nasal cavity contains millions of olfactory receptors, enabling the detection of airborne chemical molecules. This combination of functions makes the nose critical for both respiration and the sense of smell.