Pneumotaxic Centre
நியூமோடாக்சிக் மையம்
Do not confuse the Pneumotaxic centre with the Medullary rhythmicity centre. One controls the rate; the other acts as a switch. If this centre fails, your breathing pattern loses its rhythm entirely.
The idea
The Pneumotaxic centre is located in the dorsal region of the pons varolii. It functions as a switch-off point for inspiration. By limiting the duration of inspiration, it indirectly alters the respiratory rate. Increased signals from this centre shorten the inspiratory phase, leading to an increased breathing rate.
Why it matters
It acts as a switch-off point for inspiration, thereby controlling the respiratory rate and pattern.
NEET lens
NEET focuses on the location (Pons) and the function (reducing duration of inspiration). Do not mark 'Medulla' for Pneumotaxic centre. Remember: Pneumotaxic = Pons; Rhythmicity centre = Medulla.
Clinical significance
Damage to the pons often results in apneustic breathing, characterized by prolonged, gasping inspirations. This indicates a loss of the 'off-switch' mechanism. The body loses its ability to fine-tune gas exchange, leading to severe respiratory distress.
Introduction
The pneumotaxic centre is a neural centre in the upper pons (part of the brainstem) that modulates the respiratory rhythm generated by the medullary respiratory centre by limiting the duration of inspiration.
Core concept
Location: Upper pons (parabrachial nucleus). Function: sends inhibitory signals to the medullary inspiratory centre → terminates inspiration → shorter inspiration = higher breathing rate. When pneumotaxic centre is active: breathing is faster and shallower. When pneumotaxic centre is weak/absent: breathing is slow and deep (apneustic breathing). Interaction with apneustic centre (lower pons): apneustic centre prolongs inspiration. Pneumotaxic centre inhibits apneustic centre. Net result: normal controlled breathing rhythm.
Go deeper
The pons-medulla interaction creates the breathing rhythm: Medulla (DRG) → generates inspiration. Pneumotaxic centre (pons) → says 'enough, stop inspiring.' Apneustic centre → would cause prolonged gasping without pneumotaxic inhibition. Normal quiet breathing = medulla + pneumotaxic centre interaction.
From Class 10
The basic breathing rhythm from the medulla needs fine-tuning. The pneumotaxic centre in the pons adjusts the rhythm to prevent over-breathing.