central control of respiration
chemical control of respiration
- Central chemoreceptor in medulla → respond to changes in CSF pH (so only indirectly responding to arterial pCO2)
- blood brain barrier impermeable to HCO3 and H+!
- Peripheral chemoreceptors in carotid body and aortic bodies → respond to changes in pO2/pH/pCO2
respiratory centres of control
Periodicity comes from groups of neurons in brainstem
medullary respiratory group
ventrolateral region:
- Pre-Botzinger complex = generation of respiratory rhythm
groups of neurons with intrinsic firing rhythms:
- ventral respiratory group = stimulates expiration
- dorsal respiratory group = stimulates inspiration
modulated by CN 9 and 10 (which terminate in solitary tract close by)
pneumotaxic centre (pons)
- regulation of inspiration volume and RR
- strong signal = ↑ RR, ↓ duration of inspiration (think rapid shallow breathing)
apneustic centre (pons)
- stimulates inspiratory area of medulla, but who knows if it is clinically relevant
voluntary control of respiration
- via cortical motor neurons in pyramidal tracts