PhysiologyTier 1Medical Sciences concept

Hormonal control of ventilation

Core concept

  • The baseline drive is chemoreceptor, not hormonal
    • Central chemoreceptors (ventral medulla) - respond to CSF [H+] from CO2 diffusing across the blood-brain barrier; ~80% of the resting CO2 response; slow (minutes)
    • Peripheral chemoreceptors (carotid > aortic bodies) - respond to PaO2 (only below ~60 mmHg), PaCO2, [H+] and K+; fast (seconds); the only sensor of hypoxia
  • Hormones modulate the SLOPE and the SET-POINT of that response
HormoneEffect on ventilationMechanism
ProgesteroneSTIMULANT - inc central chemosensitivity to CO2Hypothalamic/medullary progesterone receptors
OestrogenStimulant; upregulates progesterone receptorsPermissive for progesterone effect
Thyroid hormoneStimulant - inc CO2 and hypoxic drive, inc BMRHypothyroidism blunts both drives
TestosteroneDestabilises breathing during sleep, inc upper airway collapsibilityContributes to male OSA predominance
Cortisol/glucocorticoidsMild stimulant
LeptinStimulant - a key ventilatory drive signal in obesityLeptin resistance -> obesity hypoventilation syndrome
AdrenalineStimulant

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