T-helper cells express the following surface molecules: 

This group of proteins is activated by a series of reactions, in which one activated chemical then activates another; and promotes inflammation, phagocytosis, and cell lysis:

Hyperventilation causes retention of carbon dioxide and an increase in the hydrogen ion concentration of the blood.

The air in the conducting zone that does not reach the respiratory zone is called:

Where on the figure is the trachea?  Enter the corresponding letter for this structure.

What is the epithelium in the nasal mucosa?

Which cells in the alveoli produce surfactant?

This structure seals the nasopharynx during swallowing:

This structure prevents entry of food particles into the trachea upon swallowing:

The two main muscles of inspiration are the diaphragm and the internal intercostal muscles