How is alveolar ventilation regulated?
This is a core topic (syllabus Level 1) and a high level of understanding was expected. Overall
candidates failed to demonstrate sufficient depth and breadth in their knowledge. A
structured response considering the three basic elements underpinning the control of
alveolar ventilation (the Sensors, Central integration and control and the Effectors) was core
material. A detailed description of each was expected.
Carotid body glomus
|Aortic glomus cells - in the aortic arch, subclavian arteries and pulmonary trunk||
(branch of the vagus)
|Mechanoreceptors in bronchial and lung tissue||
|Controller||Role||Efferents and effectors|
|Nucleus retroambigualis||Expiratory function||
Upper motor neuron axons to contralateral expiratory muscles
|Nucleus paraambigualis||Inspiratory function||
Upper motor neuron axons to contralateral inspiratory muscles
|Nucleus ambiguous||Airway dilator function||
Vagus nerve: to (larynx, pharynx and muscularis uvulae)
Glossopharyngeus muscle to stylopharyngeus muscle
|Pre-Bötzinger complex||Respiratory pacemaker ("central pattern generator")||Interneurons connecting to other respiratory control regions|
|Bötzinger complex||Expiratory function||
Inhibitory interneurons to phrenic motor neurons and other respiratory control regions
|Pontine respiratory group||
Integrates descending control of respiration from the CNS
|Interneurons connecting to other respiratory control regions|
|Cerebral cortex||Volitional and behavioural respiratory control||Pontine respiratory group|
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