Lesson 19

Lesson 19: Neural Control of Ventilation

• Location of Respiratory Center: Reticular activating system in medulla and pons.

• Primary Function: Regulates speed and depth of breathing to maintain PaCO2 and PaO2.

Input Sources

• Receives signals from:

  • Central and peripheral chemoreceptors

  • Lung stretch receptors

Integration and Response

• Integrates incoming signals and regulates:

  • Diaphragm

  • Intercostals

  • Accessory muscles

• Cerebral Cortex Role: Modifies respiratory responses.

Medullary Respiratory Centers

• Dorsal Respiratory Group (DRG):

  • Active during inspiration

  • Considered the primary respiratory pacemaker (traditional view).

• Ventral Respiratory Group (VRG):

  • Active during expiration

  • Contains pre-Bötzinger complex.

Pontine Respiratory Centers

• Pneumotaxic Center (Upper Pons): Inhibits DRG, controls inspiration duration.

• Apneustic Center (Lower Pons): Stimulates DRG, promotes inspiration.

Regulation Factors

• Respiratory Rate and Pattern Determination:

  • Neural control (medulla)

  • Chemical control (central and peripheral chemoreceptors)

  • Baroreceptors (lungs)

Summary of Components

• Breath regulation involves a reflex arc comprising:

  • Sensors

  • Afferent pathways

  • Control centers (medulla and pons)

  • Efferent pathways

  • Effector organs (respiratory muscles)

Key Takeaways

• DRG: Primary pacemaker (traditional) vs. Central pattern generator (new understanding).

• Understand the roles of the medullary and pontine centers in breathing control.