Question

Dorsal respiratory group of respiratory centre responsible for

• A. Expiration
• B. Force Expiration
• C. Inspiration
• D. Terminate Inspiration

Hint:

Associate DRG with normal, quiet breathing, which is driven by active Inspiration. VRG is recruited primarily during high-demand states requiring forced ventilation.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Quiet, rhythmic breathing is controlled by groups of bilateral neurons located within the medulla oblongata and pons of the brainstem.

Step 3: Detailed Explanation:
The medullary respiratory center contains two main neural assemblies:
1. Dorsal Respiratory Group (DRG): Composed primarily of inspiratory neurons. These neurons emit repetitive, periodic bursts of action potentials (known as the inspiratory ramp signal) that travel down to the diaphragm and external intercostals, initiating normal inspiration.
2. Ventral Respiratory Group (VRG): Contains both inspiratory and expiratory neurons. It remains largely inactive during quiet breathing but becomes highly active during forced or heavy breathing (regulating forced expiration).
The termination of inspiration is primarily regulated by the pneumotaxic center in the pons.

Step 4: Final Answer
The dorsal respiratory group is specifically responsible for driving inspiration.