Basic and Clinical Sciences (BCSE) Practice Exam

Which part of the brain is responsible for limiting inspiration to increase respiratory rate?

1. Pneumotaxic center

2. Dorsal respiratory group

3. Ventral respiratory group

4. Medullary respiratory center

The correct answer is: Pneumotaxic center

The pneumotaxic center plays a critical role in regulating the rhythm and rate of breathing by providing inhibitory signals to the medullary respiratory centers. It is located in the pons of the brainstem and helps to fine-tune respiratory patterns by limiting the duration of inhalation. This limitation enhances the respiratory rate by promoting a quicker transition between inspiration and expiration, thereby ensuring that breathing remains efficient and adequately meets the body's metabolic demands, especially during times of increased activity. In contrast, other regions such as the dorsal and ventral respiratory groups primarily facilitate inspiration and expiration without specifically limiting the duration of inspiratory effort in the way that the pneumotaxic center does. The medullary respiratory center is involved in the automatic control of breathing but relies on inputs from areas like the pneumotaxic center to adjust the overall respiratory patterns. The integrated functionality of these centers allows for a well-coordinated respiratory response to varying physiological requirements, particularly under conditions that necessitate increased ventilation.