Anaes · Applied cardiovascular & respiratory physiology

Control of ventilation

Also known as Respiratory centres · Central chemoreceptors · Peripheral chemoreceptors · Carotid body · CO2 ventilatory drive · Hering-Breuer reflex

Ventilation is controlled automatically by a brainstem network that matches alveolar ventilation to metabolic demand, and it does so chiefly by tracking arterial carbon dioxide. The framework rests on five exam-critical ideas: the automatic rhythm of breathing is generated in the medullary respiratory centres (dorsal and ventral respiratory groups), shaped by pontine pneumotaxic and apneustic centres; the dominant ventilatory drive is carbon dioxide, sensed by central chemoreceptors on the ventral medulla that respond to the hydrogen ion concentration of cerebrospinal fluid (which CO2 crosses the blood-brain barrier to set); the peripheral chemoreceptors in the carotid and aortic bodies are the principal sensors of arterial oxygen (and also respond to CO2 and pH), and they drive the hypoxic ventilatory response; ventilation is a negative-feedback loop — sensors feed the controller, which drives the effectors, which set the arterial gases that feed back; and anaesthesia, opioids and the volatile agents depress both the carbon dioxide and the hypoxic ventilatory responses, which is why the anaesthetised and the opioid-dosed patient hypoventilate. Built on the carotid body and ventilatory acclimatisation study (MacDonald 2026), the carotid body amino-acid modulation study (Gold 2026), the NTS-to-medulla GABAergic study (Shao 2026), the acid-sensing ion channel central chemoreception study (Zhu 2024), the hypoxia central circuits study (Wang 2026), and the ventilatory CO2 response study (Ekman 2025).