| A | B | 
| Human Respiratory System | Composed of a network of passageways, which permits air to flow from the external environment and into the lungs | 
| Nasal Cavity | Lined with a ciliated mucus membrane | 
| Ciliated mucus membrane | Filters, warms, and moistens air | 
| Pharynx | Known as the throat region | 
| Larynx | Contains vocal cords that vibrate and produce sound as air passes through | 
| Epiglottis | A cartilaginous flap that covers the trachea when swallowing food | 
| Trachea | Known as the windpipe | 
| Trachea | Kept open by rings of cartilage | 
| Trachea | Lined with a ciliated mucus membrane | 
| Bronchi | Kept open by rings of cartilage | 
| Bronchi | Trachea divides into two major divisions known as | 
| Bronchioles | The bronchi subdivide many times forming smaller tubules known as | 
| Bronchioles | Lack cartilage rings | 
| Alveoli | Tiny bronchioles subdivide and terminate (end) with structures known as | 
| Alveoli | Are thin, moist and surrounded by capillaries | 
| Alveoli | Are the functional units for gas exchange between the lung and the blood | 
| Alveoli | Increase surface area for gas exchange in the lungs | 
| Diaphragm | Muscle that forms the floor of the chest cavity and aids in breathing | 
| Oxyhemoglobin | In the blood, hemoglobin binds with oxygen from | 
| Bicarbonate ions | Carbon dioxide is carried primarily in the plasma | 
| Bronchitis | Inflammation of the membrane of the bronchial tubes | 
| Asthma | An allergic response characterized by constriction of the bronchial tubes | 
| Emphysema | Disease in which the walls of the alveoli breakdown | 
| Pneumonia | The alveoli become filled with fluid, preventing gas exchange between the alveoli and the capillaries |