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Mechanism of Breathing pp. 174-176 1. Define inspiration, expiration inspiration is also called inhalation, or moving air into the lungs expiration is also called exhalation, it moves air out of the lungs 2. Where are the intercostal muscles? The muscles that along with the diaphragm control the contraction and pushing out of the lungs. When they contract the rib cage moves outwards and upwards 3. Where is the diaphragm muscle? Below the lungs. It becomes dome shaped or flat to pull in air.

4. The lungs are in a "sealed" off thoracic cavity. Describe this cavity. Why is it considered "sealed"? because the diaphragm separates it from everything else. And the rib cage makes a little house for it.

5. Describe the diaphragm and intecostal muscles during inspiration. During inspiration, the thoracic cavity and lungs expand so that air is drawn in, the diaphragm moves downwards to pull air in and the intecostal muscles move the ribs up and out. 6. Air does NOT force open the lungs. So why does air enter the lungs? Because the intecostal muscles and the diaphragm create system of low pressure so that all the air is sucked in. creates a vacuum. 7. Passive Recoil occurs during expiration. What does that mean? This is when you are relaxing and not doing anything that would cause you to breath hard and instead of the diaphragm and intecostal muscles going the opposite way, they just relax and air goes out. 8. Why is air pushed out during expiration? Because new air has to get inwards. It is because the diaphragm and the intecostal muscles go the opposite way, or just relax and it makes a high pressure system in your lungs and the air goes out. 9. How can you achieve maximum inspiratory effort? By using other muscles such as your back, chest and neck. 10. How can you force expiration which is usually passive? By exercising and doing something that makes you breathe hard. The book says “heavy exercise” 11. Do you use your total lung capacity when you breathe? What do you use? No you only use your tidal volume when you breathe normally. 12. Why are the nasal cavities, trachea, bronchii, and bronchioles considered "dead air space"? because air stuck In these are not used for anything. They are dead, the air in them never reaches the lungs if it is at the end of the breath. 13. How should you breathe to get the most fresh air to your alveoli? Why? To ensure that newly inhaled air reaches the lungs, it is better to breathe slowly and deeply.