Video Transcript
Complete the following. As the air travels in the upper respiratory system, through the nose, mouth, pharynx,
and trachea, it gets blank by the mucus-secreting epithelium. (A) Moistened, warmed, and cleansed. (B) Warmed, dried, and filtered. (C) Pressurized and moistened.
This question asks us about what happens to air as it is inhaled by the upper
respiratory system. The upper respiratory system, or upper respiratory tract, refers to the nose, mouth,
pharynx, and larynx. The larynx connects with the upper part of the trachea, which connects to the
lungs. As air moves through these structures, it comes into contact with the epithelial cell
layers lining each passage. Let’s discuss some of the benefits of these mucus-secreting epithelial cells.
The secreted mucus can help to trap foreign particles and harmful molecules that
might be floating in the air. These particles can then be pushed toward the digestive system due to the action of
ciliated cells. This effectively cleanses the incoming air before it reaches the lungs.
The mucus-secreting epithelium can also help keep the air moist. This is important to maintain the structural integrity of the respiratory system. A high concentration of water vapor in the inhaled air will prevent the alveoli in
the lungs from drying out.
The mucus-secreting epithelium also acts to help warm the incoming air to further
protect the delicate structures of the lung.
Now that we’ve reviewed some functions of the upper respiratory system and the
mucus-secreting epithelium, we should be able to answer our question correctly.
In the statement “As the air travels in the upper respiratory system, through the
nose, mouth, pharynx, and trachea, it gets blank by the mucus-secreting
epithelium.” The option that correctly fills in the blank in the statement is answer choice (A)
moistened, warmed, and cleansed.
