| Inspiration | Expiration |
| 1. Inspiration is an active process. | 1. Expiration is a passive process. |
| 2. During inspiration diaphragm contracts and becomes flattened. | 2. During expiration diaphragm relaxes and becomes dome shaped. |
| 3. During inspiration intercostal muscles contract. | 3. During expiration intercostal muscles relax. |
| 4. During inspiration ribs are pulled outwards and sternum is raised. | 4. During expiration ribs are pulled inwards and sternum is lowered. |
| 5. During inspiration the space in the thoracic cavity increases. | 5. During expiration the space in the thoracic cavity decreases. |
| 6. During inspiration pressure in the lungs decreases. | 6. During expiration pressure in the lungs increases. |
| 7. During inspiration the volume of the lungs increase. | 7. During expiration the volume of the lungs decreases. |
| 8. During inspiration air comes inside the body. | 8. During expiration air goes out of the body. |
