PHED-4547EL Lecture Notes - Lecture 15: Pulmonary Alveolus, Pulmonary Pleurae, Breathing
27 Apr 2020
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Document Summary
Respiratory system oxygenates blood and removes carbon dioxide. Circulatory system transports gases in the bloodstream. Alveoli: o2 and co2 exchange; surrounded by alveolar septum (which contains capillaries); have cells that produce surfactant (decreases surface tension) Lung divided into lobes consisting of smaller units or lobules. Acinus or respiratory unit: functional unit of lung. Gases diffuse among blood, tissues, and pulmonary alveoli due to differences in their partial pressures: alveolar air, po2 105 mmhg, pco2 35 mmhg. Requirements for efficient gas exchange: large capillary surface area in contact with alveolar membrane, unimpeded diffusion across alveolar membrane, normal pulmonary blood flow, normal pulmonary alveoli. Pleura: thin membrane covering lungs (visceral pleura) and internal surface of the chest wall (parietal pleura) Pleural cavity: potential space between lungs and chest wall. Evaluate efficiency of pulmonary ventilation and pulmonary gas exchange. Tested by measuring volume of air that can be moved into and out of lungs under normal conditions.
