Mechanics of Respiration Inspiration Resting Diaphragm Active Diaphragm

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Mechanics of Respiration • Expiration • Resting • passive process • elastic properties of

Mechanics of Respiration • Expiration Spine • Active • Internal intercostals Internal Intercostals ribs

Mechanics of Inhalation Patm Palveolar Rest Copyright © 2006 by Elsevier, Inc. Palveolar Inhalation

Movement of Air In and Out of Lungs • Pleural Pressures – Resting –

Volume Change (liter) Pressure and Volume Changes During Breathing. 50. 25 0 +2 0

Pulmonary Volumes Figure 37 -6; Guyton & Hall Copyright © 2006 by Elsevier, Inc.

Definitions of Dead Space Anatomic Dead Space Physiologic Dead Space Low Blood Flow Copyright

Compliance of Lungs • Determined by elastic forces – lung tissue – surface tension

Control of Bronchiolar Diameter • Nervous – Sympathetics • 2 receptors dilate – Parasympathetics

Airway Resistance during Forced Exhalation Guyton & Hall Copyright © 2006 by Elsevier, Inc.

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Mechanics of Respiration • Expiration • Resting • passive process • elastic properties of lung • Active • Abdominals decrease chest volumes Active exhalation abdominal compression Active inspiration abdominal relaxation Copyright © 2006 by Elsevier, Inc.

Movement of Air In and Out of Lungs • Pleural Pressures – Resting – Inspiration -5 cm H 20 -8 cm H 20 • Alveolar Pressure – Resting – Inspiration – Expiration Copyright © 2006 by Elsevier, Inc. 0 cm H 20 -1 cm H 20

Volume Change (liter) Pressure and Volume Changes During Breathing. 50. 25 0 +2 0 Pressure (cm/H 2 O) -2 -4 Alveolar pressure Transpulmonary Pressure -6 Pleural pressure -8 Inspiration Copyright © 2006 by Elsevier, Inc. Expiration

Compliance of Lungs • Determined by elastic forces – lung tissue – surface tension Lung Volume • Elastic forces Exhalation Inhalation -4 -8 Change in Pleural Pressure Copyright © 2006 by Elsevier, Inc.

Control of Bronchiolar Diameter • Nervous – Sympathetics • 2 receptors dilate – Parasympathetics • Acetylcholine constrict • Humoral – Histamine, acetylcholine » Constrict – Adrenergic ( agonists) » Relax Copyright © 2006 by Elsevier, Inc.