Describe the features of the nasal cavity that moisten, clean, and warm the air as it passes through this cavity on its way to the lungs.
The nasal cavity plays a crucial role in preparing the air we breathe for its journey to the lungs. It possesses several features that help moisten, clean, and warm the air before it reaches the delicate lung tissues. Let's break down these features one by one:
1. Moistening: The nasal cavity contains a network of blood vessels close to its surface called nasal mucosa. These blood vessels release moisture, creating a humid environment. As the incoming air passes through the nasal cavity, it picks up this moisture. This moisture helps to prevent the respiratory passages from becoming too dry, ensuring the optimal functioning of the respiratory system.
2. Cleaning: The nasal cavity has a lining of mucus-producing cells called goblet cells. These cells continuously secrete a sticky substance known as mucus. As air flows through the nasal cavity, the mucus acts as a trap, capturing airborne particles such as dust, allergens, bacteria, and viruses. The mucus, along with these trapped particles, is then swept towards the back of the throat by tiny hair-like structures called cilia. This process helps to remove harmful particles from the air, preventing them from reaching the lungs.
3. Warming: The nasal cavity also helps in regulating the temperature of the inhaled air. The extensive blood supply in the nasal mucosa warms up the air as it passes over these blood vessels. The warm air ensures that the lungs receive air at a temperature suitable for efficient gas exchange, as extreme cold or hot air can be detrimental to the respiratory system.
To summarize, the nasal cavity moistens the air with moisture released from the blood vessels, cleans the air by trapping particles with mucus and moving them to the throat for elimination, and warms the air through its extensive blood supply. These functions collectively contribute to ensuring that the air we breathe is appropriately conditioned before it reaches the lungs.