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PHGY 210 - Respiration

PHGY 210 - Respiration - 7 July 4 2011 6:05 PM RESPIRATION...

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RESPIRATION Structure of the lungs and chest wall 1. The primary function of respiration is gas exchange In mammals, gas exchange occurs in the lungs During inspiration, air rich in O 2 in inhaled During expiration, CO 2 produced during oxidative processes of the body is exhaled Both gases are transported by the blood Function of respiration A. Cean the air of big dust particles - Inhaled air passes over a complex series of surfaces when it goes through the nose: nasal septum and nasal turbinates From the nose, warmed and moistened air flows through the common passages for air and food (pharynx) and continues through the larynx Air finally reaches the periphery of the lungs via the trachea and bronchi The lungs and the airways share the chest cavity with the heartm the great vessels and the esophagus The airwais consist of a series of tubes that branch and become narrower, shorter and more numerous as they penetrate into the lungs The trachea divides into 2 main bronchi , each of which divides into lobar and segmental bronchi. The right main bronchus has 3 lobar bronchi, while the left main bronchus divides into only 2 lobar bronchi. The smallest airways without alveoli are the terminal bronchioles - The segmental bronchi divide further into smaller branches Pleura: thin cellular sheet attached to the thoracis cage interior (parietal pleura) and, folding upon itself, attached to the lunch surface (viceral pleura) Forms two enclosed pleural sacs in the thoracic cage Air will just flow the air gradient - The pressure in the pleural space is negative If chest enlarges, lungs will too - The intrapleural fluid couples the lungs to the chest Pneumothorax: chest expands but lungs to not because pressure is 0 Pleura and pleural surfaces The respiratory tract B. ---> are is conducted towards the alveoli ---> start seeing alveoli *gas exchange --->zone composed only of alveoli 7 - January 19 2011 July 4, 2011 6:05 PM Respiration Page 1
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the airways are divided into 2 zones: conducting zone (made up of the conducting airways) and respiratory zone The conducting airways consist of the airways from the mouth and nose openings, all the way down to the terminal bronchioles The conductive airways do not contribute to gas exchanges, and are thus said to compose the anatomical dead space The respiratory part of the lungs (the respiratory zone) begins where the terminal bronchioles divides into respiratory bronchioles, which have some alveoli opening in their lumena Beyond the respiratory bronchioles are the alveolar ducts lined with alveoli Because of such abundant branching of the airways, the respiratory zone makes up most of the lungs The smallest physiological unit of the lungs (distal to the terminal bronchioles) is the acinus Conduction and respiratory zones C.
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PHGY 210 - Respiration - 7 July 4 2011 6:05 PM RESPIRATION...

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