| Chapter 20 | Circulation and Respiration |
| 20.1 | The Circulatory System |
| Arteries: Highways from the Heart | |
| Capillaries: Where Exchange Takes Place | |
| Veins: Returning Blood to the Heart | |
| The Lymphatic System: Recovering Lost Fluid | |
| 20.2 | Blood |
| Blood Plasma: The Blood's Fluid | |
| Blood Cells: Cells That Circulate Through the Body | |
| Erythrocytes Carry Hemoglobin | |
| Leukocytes Defend the Body | |
| Platelets Help Blood to Clot | |
| 20.3 | The Heart and How It Works |
| Circulation Through the Heart | |
| How the Heart Contracts | |
| Monitoring the Heart's Performance | |
| 20.4 | The Respiratory System |
| The Lungs | |
| The Mechanics of Breathing | |
| How Respiration Works: Gas Exchange | |
| O2 Transport | |
| CO2 Transport | |
| NO Transport | |
| How the Brain Controls Breathing | |
| 20.5 | Lung Cancer and Smoking |
| The Nature of Cancer | |
| What Causes Lung Cancer? |