Lesson 11: The Respiratory System (page 3 of 19)

Inhalation (breathing in) occurs when the diaphragm contracts.


The Upper Respiratory Tract


Proper breathing involves drawing air in through the nose. The nasal cavity warms and moistens the air and filters it of impurities. Tiny hairs and sticky mucous membranes trap foreign materials before they can enter the delicate tissues of the lungs. Structures in the nasal cavity called concha increase the surface area allowing maximum efficiency.The sinuses are hollow areas, or cavities, in the bones of the skull that are lined with mucous membranes and that open into the nasal cavity. The sinuses provide resonance for the voice. When the sinuses are inflammed and filled with mucus the voice has a different quality, often referred to as “nasal” in character. Sinuses

The pharynx refers to the part of the respiratory tract behind the nasal cavity and mouth, in other words, the throat. Inflammation of the pharynx is referred to as pharyngitis [pharynx + itis, inflammation] also known as the common “sore throat.”

The nasal cavity __________ the air we breathe.


 humidifies (moistens)
 All of the above.

(Select the best answer and click on the “Continue” button.)