Pneumotaxic centre is present on pons varoli which maintain cut off point of breathing

The Pneumotaxic Centre is present in the Pons Varolii.

The pneumotaxic center, also known as the pneumotaxic area or nucleus, is a small group of neurons located in the pons varolii, which is a part of the brainstem. It is responsible for regulating the rate and depth of breathing.

Function of the Pneumotaxic Centre:

The primary function of the pneumotaxic center is to inhibit inspiration and control the rate and depth of breathing. It works in conjunction with the medullary respiratory center to fine-tune the respiratory rhythm and prevent overinflation of the lungs.

Regulation of Breathing:

The medullary respiratory center, located in the medulla oblongata, generates the basic rhythm of breathing. It consists of two main centers, the dorsal respiratory group (DRG) and the ventral respiratory group (VRG). The DRG primarily controls inspiration, while the VRG controls both inspiration and expiration.

The pneumotaxic center, located in the pons, sends inhibitory signals to the medullary respiratory center, particularly the DRG. This inhibitory input from the pneumotaxic center limits the duration of inspiration and prevents excessive lung inflation. As a result, it helps regulate the rate and depth of breathing.

Interaction with the Dorsal Respiratory Group:

The pneumotaxic center interacts with the dorsal respiratory group by modulating the duration of inspiration. As the inspiratory neurons in the DRG become more active, they send signals to the phrenic nerves, which control the contraction of the diaphragm. The pneumotaxic center inhibits these inspiratory signals, limiting the duration of inspiration and promoting a shorter inspiratory phase.

Summary:

The pneumotaxic center, present in the pons varolii, is responsible for regulating the rate and depth of breathing. It works in conjunction with the medullary respiratory center to fine-tune the respiratory rhythm and prevent overinflation of the lungs. By inhibiting the inspiratory signals from the dorsal respiratory group, it controls the duration of inspiration and helps maintain a balanced respiratory pattern.