Exercise 33 Pulmonary Ventilation PDF

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Pulmonary Ventilation...

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Exercise 33: Pulmonary Ventilation   

Respiratory system supplies the oxygen needed to produce adenosine triphosphate (ATP) Removes carbon dioxide from the bloodstream Air moves from areas of high pressure to areas of low pressure ○ Boyle’s Law: Pressure of a gas in a closed chamber is inversely proportional to the volume of that container.  Increase in Volume → Decrease in Pressure  Decrease in Volume → Increase in Pressure

Pulmonary Ventilation: (Breathing) The movement of air between the atmosphere and the lungs that occurs when we inhale and exhale.  Increase in Lung Volume = Decrease in Pressure → Causes air to ENTER the lungs.  Decrease in Lung Volume = Increases in Pressure → Causes air to EXIT the lungs. Changing Thoracic and Lung Volume (Bolded muscles are used only with forced inhalation/exhalation) Muscles that increase lung volume and thoracic cavity:  External Intercostals = Elevate ribs  Sternocleidomastoids = Elevates the sternum  Scalenes = Elevate 1st and 2nd ribs  Pectoralis Minor = Elevates 3rd, 4th, and 5th ribs  Diaphragm = Flattens when contracted Muscles that decrease lung volume:  Internal intercostals = Depress ribs  Abdominal muscles = Compress abdominal contents, increases abdominal pressure, and forces diaphragm superiorly ○ External oblique, internal oblique, transversus abdominis, and rectus abdominis Know Table 33.1 in lab book (page 556) Know Figure 33.1 in lab book (page 557) Know Table 33.2 in lab book (page 559) Know Figure 33.3 in lab book (page 559) Pressure Changes during Pulmonary Ventilation As thoracic cavity expands (increases volume) it pulls the parietal pleura out with it.  Pleural cavity pressure increases → Decrease in intrapleural pressure ○ Pulls the lungs (visceral pleura) outward: caused by surface tension from pleural fluid. As lungs increase in volume:  Alveolar pressure decreases to below atmospheric pressure ○ Causing air to enter the lungs. When thoracic volume decreases:  Lungs size decreases  Intrapleural pressure and alveolar pressure increase → Air leaves the lungs...