Lecture 5.1: Chemical Control of Ventilation Flashcards
What is Eupnoea?
Normal Breathing
What are the 2 significant groups of medullary neurons?
• Dorsal Respiratory Group (DRG) • Ventral Respiratory Group (VRG)
What is the role of the Dorsal Respiratory Group (DRG)?
• It receives input from peripheral
chemoreceptors
• And other types of receptors via the
vagus and glossopharyngeal
nerves
• These impulses generate
inspiratory movements and are
responsible for the basic rhythm of
breathing
What is the role of the Ventral Respiratory Group (VRG)?
• The VRG contains both inspiratory
and expiratory neurons
• The ventral respiratory group of
neurons are active in forceful
breathing and inactive during quiet,
restful respirations
• The VRG sends inhibitory impulses
to the apneustic center
• Many expiratory neurons don’t fire
during eupnoea, those that do don’t
initiate contraction of expiratory
muscles
• Botzinger complex may inhibit some
neurons in DRG
• Pre-Botzinger complex may be the
pacemakers
What is the Apneustic Center?
The apneustic center sends signals for inspiration for long and deep breaths
Where is the Ventral Respiratory Group (VRG) located?
• The VRG is located in the ventrolateral
region of the medulla
• Retrofacial nucleus, the nucleus
ambiguus, the nucleus para-
ambigualis, and the nucleus
retroambigualis
• Inspiratory and expiratory neurons
Where is the Dorsal Respiratory Group (DRG) located?
• The dorsal respiratory group is located
in the distal portion of the medulla
• Located nucleus tractus solitaries
• Many projections to VRG (but receives
few in return)
What is the Pneumotaxic Center?
• The pneumotaxic center controls
both the rate and the pattern of
breathing
• The pneumotaxic center is
considered an antagonist to the
apneustic center, (which produces
abnormal breathing during
inhalation) cyclically inhibiting
inhalation
What receptors sense O2?
• Peripheral chemoreceptors
• Those in the carotid body more important than aortic
body