Respiratory System

Respiratory System - Conduction zone parts of the...

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Conduction zone – parts of the respiratory system that participate only in ventilation Respiratory zone – participate in actual gas exchange. The respiratory system (trivially) regulates heat dissipation. Inhaled air: nose nasal cavity pharynx larynx trachea bronchi terminal bronchioles respiratory bronchioles alveolar ducts alveoli. - Conduction zone Columnar cells line the respiratory tract: these cells are too thick for gas exchange; they merely provide a conduit for air - Most columnar cells are too thick for any exchange of nutrients – that’s why GI tract cells and alveolar cells of the respiratory tract are squamous (except for the esophagus and the trachea, which are both most likely columnar) Goblet cells – secrete mucous Alveolar macrophages patrol the alveoli, engulfing foreign particles. Consider: in “preemies” (babies that are born prematurely), there is not sufficient surfactant within the lungs this means that the babies’ lungs are more prone to collapse Cystic fibrosis – inadequate ion secretion decreases fluid movement in the airways. - Without the secretion of saline beneath the mucus, cilia become trapped in the sticky mucus. - Mucus cannot be cleared, bacteria colonize the airways. Because atmospheric pressure is relatively constant, pressure in the lungs must be higher or lower than the atmospheric pressure for air to flow between the atmosphere and the alveoli Air moves into the lungs the intercostals and the diaphragm contract, increasing the volume in the thoracic cavity causes a decrease in pressure in the thoracic cavity - Alveolar pressure decreases as well. - When the diaphragm contracts, we are inspiring (i.e. the diaphragm moves downward, and the pressure in the thoracic cavity is lower than the atmospheric pressure, driving the movement of oxygen into the lungs. This is an active process ) -
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Respiratory System - Conduction zone parts of the...

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