Air enters the upper respiratory system through the____________________, which are the openings that lead into the nasal cavity. The air moves through passageways that are formed by the____________________, which protrude into the cavity. 2. From the nasal cavity, air flows into the first part of the pharynx, which is the____________________. Then, it flows through the other 2 parts of the pharynx, which are called the____________________and____________________. 3. Air then makes its way into the____________________. This structure includes 9 laryngeal cartilages that____________________. The largest of these cartilages is the____________________. Another significant part of the larynx, the____________________, covers the opening to the trachea during swallowing to prevent food from accidentally entering the respiratory tract. This structure is composed of____________________. 4. Then air moves into the first part of the lower respiratory system, the____________________, which has rings composed of____________________. This structure branches into 2____________________, 1 for each lung. 5. Air flows through the bronchi, which get____________________as you move from primary to secondary to tertiary, eventually terminating in____________________, which are tiny air sacs where gas exchange occurs. 6. Air flows from the bronchi into the lungs medially through the____________________. The____________________lung has 3 lobes, whereas the____________________lung has 2. There are grooves on the surface of the lungs, called____________________ which separate the lungs into lobes. The____________________lung is slightly larger than the____________________ lung due to its position in relation to the heart.