| A | B |
|---|
| What does the lower end of the trachea divide into? | the bronchial tubes |
| What hold these tubes open? | rings of cartilage |
| What are they lined with? | Cilia |
| the bronchi divide filling each lung with a network of tiny tubes called what? | bronchile |
| At the end of each bronchiole tube is an expansible air sac called what? | alveolus |
| How are the alveoli arranged? | Like clusters of grapes |
| The alveoli make up what part of the lung? | the part that expands |
| How thick are the walls of the alveoli? | 1 cell thick |
| Waht are the walls of the alveoli covered with? | capillaries |
| Why does oxygen enter the blood? | More cencentrated in the alveoli than the blood |
| Why does carbon dioxide leave the blood? | Concentration is higher in the blood than the alveoli |
| Exhaled air is __% oxygen and more than __% carbon dioxide | 16% oxygen, 4% carbon dioxide |
| Inhaled air is ___% oxygen and less than __% carbon dioxide | 21% oxygen, 1% carbon dioxide |
