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level: Control of Ventilation

Questions and Answers List

level questions: Control of Ventilation

QuestionAnswer
Describe the anatomical position of the respiratory control centre and its role in regulation of ventilation.Pneumotaxic centre – controls inspiratory time. Fourth ventricle – protects human brain from trauma via cushioning effect. Apneustic centre – leads to a gradual increase in the firing rate of the inspiratory muscles. Dorsal respiratory group (inspiration) – controls mostly inspiratorymovements and their timing. Ventral respiratory group (expiration and inspiration) – controls voluntary forced exhalation and acts toincrease the force of inspiration. Vagus and glossophraygeal – provides sensation, including taste, to the posterior third of the tongue, and also sensation to the back of the oral cavity and the oropharynx.
How does pCO2 and pH influence ventilation?O2 and H+ directly influence the respiratory centre. Peripheral H+ ions do not readily pass the blood-brain barrier H+ ions are produced when blood CO2 is elevated – CO2 +H20  H2CO3 H++ HCO3- Respiratory activity strongly influenced by fluctuations in CO2. PCO2 increased during periods of exertion or hypoventilation but is rapidly controlled via changes in VA.
Describe the effect of altered pO2 on ventilation.Low PO2exaggerates the VA response to high PCO2 Low pH exaggerates the VA response to high PCO2
How does exercise alter pO2 ventilation?VD/VT reduced due to an increase in VT during exercise. Total VE reaches 120L/min and up to 200L/min in tall athletes. An increase in VA at the onset of exercise is due to increased VT and respiratory rate. A progressive increase in VA beyond moderate exercise is primarily due to increased respiratory rate.