Neural Control of Ventilation - Involuntary Control

Overview

• Ventilation is the movement of air in and out of the lungs for gas exchange.
• Respiratory muscles contract and relax rhythmically for inspiration and expiration.

Involuntary Control of Respiration

• Involuntary respiration is controlled subconsciously.
• Primary respiratory muscles: Diaphragm and intercostal muscles.
  • Stimulated by neurons in the pons and medulla forming the respiratory control centre.
  • Neurons send impulses via phrenic and intercostal nerves to stimulate muscle contraction.
• Three main groups of neurons:
  • Ventral respiratory group: Controls expiration.
  • Dorsal respiratory group: Controls inspiration.
  • Pontine respiratory group: Controls rate and pattern of breathing.
• Expiration occurs when neurons stop firing, causing inspiratory muscles to relax.

Voluntary Control of Respiration

• Voluntary respiration is under conscious control.
• Controlled by the motor cortex in the cerebrum.
  • Receives inputs from the limbic system and hypothalamus.
  • Signals likely sent from motor cortex to spinal cord, then to respiratory muscles.

Clinical Relevance: Phrenic Nerve Paralysis

• Phrenic nerve paralysis leads to diaphragm dysfunction and breathing issues.
• Causes: Spinal cord injury, neck injury, and surgical complications.
• Patients may lose the ability to regulate their own breathing.

Additional Resources

• Further details on the mechanics of breathing can be found on the TeachMePhysiology website.

This summary covers the key aspects of neural control in both involuntary and voluntary respiration, highlighting the clinical relevance of phrenic nerve paralysis and providing insights into the respiratory control mechanisms.