Control of ventilation Flashcards
What nerve (groups) are used in inspiration?
Phrenic nerve to diaphragm
Intercostal nerves to external intercostals
Where are the respiratory centres located?
Medulla and pons
What respiratory centre sets the automatic rhythm of breathing?
DRG
Dorsal respiratory group - in the medulla
What factors modulate rhythm of breathing?
Emotion (limbic system)
Voluntary over-ride
Mechano-sensory input
Chemical composition of blood
What detects changes in the chemical composition of the blood?
Chemoreceptors
What respiratory group is responsible for controlling expiratory muscles, as well as the tongue, pharynx and larynx?
VRG
Ventral respiratory group (of neurones)
Where are the central chemoreceptors located?
Medulla
What do the central chemoreceptors respond do?
They measure changes in pCO2 in the CSF around the brain
This indirectly measures the pH of blood
Where are peripheral chemoreceptors located?
Carotid artery and the aorta
Why can central chemoreceptors not directly measure [H+]?
H+ ions cannot cross the blood-brain barrier
A decreased pCO2 will cause?
A decrease in ventilation rate
What do peripheral chemoreceptors do?
Detect changes in arterial pO2 and [H+]
They stimulate ventilation if there is a significant drop in pO2 and/or significant rise in [H+]
What classes of drugs act directly to depress the respiratory centres?
Barbiturates
Opiods
What is the effect of gaseous anaesthetics on respiratory rate?
Increase RR
But decrease Tidal volume
Communication between the Ventral respiratory group and the dorsal respiratory group takes place through tho…
pre-Botzinger complex
