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Describe how the mechanism of ventilation is controlled. Describe the roles of the phrenic nerves and medulla in generating a basic breathing rhythm.
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Describe how the mechanism of ventilation is controlled.Describe the roles of the phrenic nerves and medulla in generating a basic breathing rhythm. Introduction The tidal flow of air into and out of the lungs is caused by differences in pressure between the thorax and the atmosphere.Air always moves from an area of higher pressure to an area of lower pressure.A ventilation mechanism ensures that a constant supply of fresh air is available to provide enough oxygen for gas exchange and to remove carbon dioxide. There are two processes of breathing- inhalation and exhalation Inhalation Air moves from high to low pressure.Hence the pressure in the lungs is low.The diaphragm muscle contracts and flattens.The external intercostals muscles contract and pull the rib cage out and up.The volume in the lung increases.This reduces the pressure in the lungs and air moves from the atmosphere(high pressure) to the lungs(low pressure) Process of breathing in Exhalation In this process the pressure...
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