PHGY 210 Lecture Notes - Lecture 11: Hypercapnia, Bronchoconstriction, Glossopharyngeal Nerve
14 May 2012
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Document Summary
Frc does not mean that the lung is empty. There is still 1. 2 l of air in the lungs at frc: respiratory failure. Respiratory failure occurs when the respiratory system is unable to do its job properly, due to failure of: 2)the neural control of ventilation (i. e. the drive to breathe); 3)the neuromuscular breathing apparatus (i. e. the respiratory muscles and their innervation): arterial hypoxia (hypoxemia) Blood hypoxia refers to deficient blood oxygenation, i. e. low pao2 and low % hb saturation. In hypoxic conditions, if pao2 decreases below 60 mm hg, o2 content in arterial and venous blood becomes lower than the normal values at sea level. There are 5 general causes of hypoxia: inhahlation of low po2 (e. g. at high altitude), hypoventilation: pao2 decreases and paco2 increases. It means that alveolar ventilation in relation to the metabolic co2 production is reduced. Vi control of breathing: voluntary vs automatic breathing.
