Nenäkäytävä

Nenäkäytävä, also known as the nasal passage or nasal cavity, refers to the space within the nose. It is the primary entrance for air into the respiratory system and plays a crucial role in breathing, olfaction, and filtering inhaled air. The nasal cavity is divided into two by the nasal septum, a wall of cartilage and bone. Each side is lined with a mucous membrane, which contains tiny hairs called cilia and produces mucus.

The functions of the nenäkäytävä are multifaceted. The mucus traps foreign particles like dust, pollen, and pathogens, while the cilia sweep these trapped substances towards the throat to be swallowed or expelled. This filtering mechanism helps protect the lungs from irritants and infections. Furthermore, the nasal passages warm and humidify the inhaled air, making it more suitable for the delicate tissues of the lungs. The olfactory receptors, responsible for the sense of smell, are also located within the upper part of the nasal cavity.

The structure of the nenäkäytävä includes several bony projections called conchae (or turbinates) on the lateral walls of each cavity. These conchae increase the surface area, further enhancing the warming, humidifying, and filtering capabilities of the nasal passages. Inflammation of the nasal passages, known as rhinitis, can result in symptoms like congestion, sneezing, and a runny nose, often caused by allergies or infections.