LEC 20: RESPIRATORY CONTROL & LUNG DISEASE

• Medulla oblongata


  Two crucial areas for respiration control
• Ventral respiratory group (VRG)


  • Generates rhythm for respiratory, coordinating diaphragm, and intercostal muscles
• Dorsal respiratory group (DRG)


  • Integrates peripheral input, communicates with VRG
• Pontine respiratory group


  Modifies breathing rhythm for smooth transitions
• Reciprocal inhibition

  Ensures coordinated inhalation and exhalation
• Chemical stimuli


  Changes in CO2, O2, and H+ levels in arterial blood
• Peripheral chemoreceptors

  • Monitors arterial PO2 and pH
  • Influences respiratory rate and depth
• Metabolic causes

  Alterations in arterial pH triggers adjustments to normalize pH
• Emotional and pain responses

  Modulates breathing via limbic system and hypothalamus
• Conscious control

  Cortex regulates breathing pattern consciously
• Pulmonary irritant reflexes


  • Triggered by inhaled irritants
  • Causes bronchoconstriction
• Inflation reflex (Hering-Breuer reflex)


  Protects lungs from overexpansion by inhibiting inspiration
• Arterial pH changes

  Respiration adjusts to normalize blood pH
• Rising PCO2 levels


  Increased breathing rate and depth
• Substantial drops in PO2


  Affect ventilation
• Pulmonary irritant reflexes & inflation reflex


  Regulate respiratory activity in response to irritants and prevents overinflation
• Volition


  Allows voluntary alteration of breathing patterns
• Emotions

  Modify respiratory rate and depth in response to emotional stimuli
• Hyperpnea


  Deeper and more vigorous respiration during exercise to ensure tissue oxygen demands are met
• Hyperventilation


  Increased depth and rate of breathing exceeding the body's metabolic needs, can lead to decreased blood CO2 levels (hypocapnia)
• Acclimatization to high altitude

  1. Increased ventilation rate

  2. Higher hemoglobin saturation

  3. Production of erythropoietin
• Effects of acclimatization to high altitude

  • Improved oxygen transport and utilization
  • Enhanced aerobic performance over time
  • Reduction in altitude sickness symptoms
  • Better adaptation to environmental stressors
• Obstructive pulmonary diseases

  Hyperinflation of the lungs due to obstructed airways
• Obstructive pulmonary diseases

  • Chronic obstructive pulmonary disease (COPD)
  • Emphysema
  • Chronic bronchitis
• Restrictive pulmonary diseases

  Limitation in lung expansion and reduced lung volumes
• Restrictive pulmonary diseases

  • Pulmonary fibrosis
  • Sarcoidosis
  • Chest wall disorders
• what are the 2 crucial areas for respiration control?

  ventral and dorsal respiratory group