Diffusion of gases is directly proportional to their concentration gradients.

Pulmonary ventilation is best defined as:

This is the sum of the tidal volume, inspiratory reserve volume and expiratory reserve volume.

Air moves out of the lungs when:

When blood pH falls (i.e., the blood becomes pore acidic), a negative feedback loop is triggered that increases the rate and depth of ventilation to remove carbon dioxide from the blood.

This is a major mediator of inflammatory responses and causes vasodilation:

What is the function of the nasal mucosa?

What is the last structure of the conducting zone?

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

T-helper cells express the following surface molecules: