Control of Ventilation Flashcards
What 2 nerves is breathing reliant upon?
Phrenic
Intercostal
What is the role of the respiratory centres?
To set automatic rhythm of breathing and adjust it in response to stmuli
What are the 4 factors that can modulate the rhythm of the respiratory sensors?
Emotion - via limbic system
Voluntary over-ride - via higher brain centres
Mechano-sensory input from the thorax
Chemical composition of the blood - detected by chemoreceptors
Which of the factors that modulate the rhythm of respiratory sensors is the most significant?
The chemical composition of the blood
What are the 2 main groups of neurons in the innervation of respiration?
DRG (Dorsal respiratory neurons)
VRG (Ventral respiratory neurons)
What muscles to the DRG innervate?
Inspiratory muscles
Which muscles do the VRG innervate? (4)
Expiratory muscles, tongue, pharynx, larynx
Where are the central chemoreceptors located and what role do they play in ventilation?
Medulla
They are the primary ventilatory drive
Where are the peripheral chemoreceptors located and what role do they play in ventilation?
Carotid and Aortic bodies
They are the secondary ventilatory drive
What do the central receptors detect?
Changes in the concentration of hydrogen ions in the CSF
What odes a rise in hydrogen ions in the CSF cause in ventilation?
Reflex stimulation of ventilation
Can CO2 or H+ ions cross the blood-brain barrier?
CO2 can cross
H+ ions cannot cross
When do peripheral chemoreceptors cause a reflex stimulation of ventialtion?
When there is a significant fall in arterial PO2 or rise in H+ ions
Which chemoreceptors respond to changes in plasma pH?
Peripheral chemoreceptors
What effect to barbiturates and opioids have on respiratory centres?
They depress respiratory centres
