Muscular layer more prominent as branching continues 3 Elastic fibers in the

Muscular layer more prominent as branching continues

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Muscular layer more prominent as branching continues 3. Elastic fibers in the wall aid breathing 4. Epithelium changes from psuedostratified ciliated to cuboidal and simple squamous (why?) D. Functions of the respiratory tubes include: 1. Distribution of air 2. Exchange of gasses between blood and air 3. Passage to remove waste gasses III. LUNGS A. Left and right lungs are separated by the mediastinum B. Enclosed by the diaphragm and thoracic cavity C. Visceral pleural peritoneum is attached to the outside D. Parietal plural lines the thoracic cavity E. Right lung has three lobes: 1. Superior 2. Middle 3. Inferior F. The left lung has two: 1. Superior 2. Inferior G. Each lobe is composed of lobules that contain:
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160 1. Alveoli, Blood Vessels, Connective Tissue IV. INSPIRATION A. Air forced into lung by atmospheric pressure B. Results from decreased in intra alveolar pressure C. When diaphragm moves down, a partial vacuum created D. Thoracic cage at the same time moves up E. Atmospheric pressure forces air into bronchial tree F. Expansion aided by surface tension that holds the pleural membrane together (Parietal, Visceral) G. Surfactant reduces surface tension to prevent collapse of the alveoli V. EXPIRATION A. Elastic recoil of tissues and surface tension within the alveoli B. Thoracic cage pushed downward, diaphragm upward VI. RESPIRATORY AIR VOLUMES A. Amount of air moving in and out during normal breathing is the tidal volume B. Additional air that can be inhaled in the inspiratory reserve volume. C. Additional air that can be expired is the expiratory reserve volume D. Residual air is the air that remain in the lung E. Vital capacity is the maximum amount of air that can be exhaled after taking the deepest breath possible F. Total lung capacity is (Vital + Residual) G. Air in alveolar dead space is not available. VII. ALVEOLAR VENTILATION A. Minute Respiratory Volume: (Tidal Volume x Breathing Rate) B. Alveolar Ventilation Rate: ((Tidal Volume – Dead Space Air) x Rate) C. Alveolar Ventilation Rate is Important in the Gas Exchange Between Alveolar Air and Blood SECTION 2: CONTROL OF BREATHING I. RESPIRATORY CENTER – MEDULLA OBLONGATA AND PONS A. Located in the medulla and pons of the brain stem B. Respiratory rhythm area included two neuron groups 1. Dorsal – Basic Breathing Rhythm 2. Ventral – Forceful Breathing C. Pneumotaxic area Regulates the breathing rate
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161 II. FACTORS THAT AFFECT BREATHING A. Chemical, stretching of lungs, emotional state B. Chemo sensitive area are connected to the respiratory center: 1. CO 2 + H 2 O create carbonic acid 2. This releases H + ions 3. Chemo sensitive areas influenced by H + 4. Stimulation increases breathing rate C. Chemosensors are found: 1. Carotid and aortic arteries 2. Sense low O 2 conditions 3. Increase breathing rate if O 2 is low D. Inflation reflex: Prevents over distention of lung E. Hyperventilation – CO 2 decreases III. ALVEOLAR GAS EXCHANGE A. Alveoli: 1. Air sacs at the distal end of the alveolar duct 2. Alveoli may have alternate passage ways into other alveoli B. Respiratory Membrane: 1. Alveolar and capillary walls 2.
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