What is the first structure in the airflow order of the upper respiratory system?

The first structure in the airflow order of the upper respiratory system is the nasal cavity. Air enters the upper respiratory system through the nostrils and passes into the nasal cavity. The nasal cavity plays several critical roles, including filtering, warming, and humidifying the air before it moves further into the respiratory tract.

From the nasal cavity, air then flows into the nasopharynx, which is often incorrectly thought to be the very first structure encountered in the airflow sequence. The correct sequence begins with the nasal cavity since it serves as the initial passage for inhaled air.

Understanding airflow dynamics in the upper respiratory system is essential for comprehending how various structures contribute to the respiratory process and their relevance in areas such as surgery or anesthesia in oral and maxillofacial practice.