lungs+dw

Mechanism of Breathing pp. 174-176 DeMarcus Waggoner 1. Define inspiration, expiration Expiration- act of expelling air from the lungs; also called called exhalation. Inspiration- Act of taking air into the lungs; also called inhalation. 2. Where are the intercostal muscles? Between the ribs. 3. Where is the diaphragm muscle? Below the lungs 4. The lungs are in a "sealed" off thoracic cavity. Describe this cavity. Why is it considered "sealed"? The rib cage, consisting of the ribs joined to the vertebral column posteriorly and to the sternum anteriorly, forms the to and sides of the thoracic cavity. The intercostal muscle lies between the ribs. The diaphragm and connective tissue from the floor of the thoracic cavity. 5. Describe the diaphragm and intecostal muscles during inspiration. When the intercostal muscle contract to it stimulates the diaphragm to contract via the phrenic nerve. 6. Air does NOT force open the lungs. So why does air enter the lungs? Because humans inhale by negative pressure. The creation of the partial vaccum in the alveoli causes air to enter the lungs. While inspiration is the active phase of breathing, the actual flow of air into the alveoli is assive. 7. Passive Recoil occurs during expiration. What does that mean? The muscles relax to release air form the lungs. 8. Why is air pushed out during expiration?

9. How can you achieve maximum inspiratory effort? Taking a relaxing deep breathe 10. How can you force expiration which is usually passive? Expirations can be forced with the use of the diaphragm and abdominal muscles. 11. Do you use your total lung capacity when you breathe? What do you use? No you do not use your total lung capacity when normally breathing. We only use 500mL 12. Why are the nasal cavities, trachea, bronchii, and bronchioles considered "dead air space"?Because those passages are not used for gas exchange. 13. How should you breathe to get the most fresh air to your alveoli? Why? It is best to breath slowly and deeply.