Explain Vagus Nerve - Neural Control of Respiration

The rhythm and depth of respiration are controlled by the reflexes from the vagus nerve.

When the lungs are inflated, there is an arrest of inspiration. When lungs are deflated, the opposite effect is observed. This reflex is called 'Hering-Breuver reflex '. When both the vagus nerves are cut, respiration becomes slow. But if the central cut end of the vagus nerve is stimulated, then the respiration becomes more or less normal. From this experiment, it can be suggested that sensory impulses through the vagus nerve help to make the respiration normal.

It was also observed that if the vagus nerve were cooled to 0°C, inflation of lungs did not cause inhibition of respiration. But if vagus nerve was warmed, inflation of lungs did not inhibit the respiration. This later effect is called paradoxical reflex of head.