What is the primary role of the VRG in respiration?

• A. Stimulate diaphragm contraction
• B. Primarily inspiratory control
• C. Facilitate expiration
• D. Regulate breathing rate

Answer: (C)

The primary role of the ventral respiratory group (VRG) in respiration is to facilitate expiration. The VRG is located in the medulla oblongata and plays a crucial role in controlling the rhythm of breathing. While it is involved in both inspiratory and expiratory actions, its most significant function is to activate muscles that promote expiration, particularly during forced breathing. This means that the VRG can stimulate muscles such as those involved in coughing and heavy expiration when the body requires increased airway clearance or when performing activities that demand more intense breathing.

Understanding the role of the VRG in expiration provides insight into its overall contribution to the respiratory process. It works in conjunction with other respiratory centers in the brain, but it is particularly noted for ensuring effective ventilation by managing the expiration phase, especially when the respiratory demand increases.