Respiratory 29 Flashcards
Where is the Rhythm of breathing established?
In the CNS
Where is breathing initiated?
In the medulla by specialized neurons
What are the three important regions that control breathing in the brainstem?
- The pontine respiratory group
- Dorsal respiratory group
- Ventral respiratory group
Which part of the brainstem are respiratory rates generated?
The ventral respiratory group
What is breathing modified by?
Higher structures of the CNS and inputs from central and peripheral chemoreceptors and mechanoreceptors in the lung and chest wall
what must neuronal networks establish for contraction of the respiratory muscles?
Automatic rhythm
At what level does the neural control of breathing occur?
At the level of the brainstem
What is the most important respiratory group in the brainstem?
The ventral respiratory group
Why is the ventral respiratory group most important?
Because both the inspiratory rhythm generator and the expiratory rhythm generator are located in this area
What kind of complex is the inspiratory rhythm generator?
A PreBötzinger complex (PreBötC)
What is the PreBötzinger complex?
A group of neurons in the ventral respiratory group that generate rhythmic contractions from the six month of gestation until your last breath
Through what pathway does the PreBötzinger complex act?
Via the polysynaptic pathway
When do PreBötzinger neurons fire?
Everytime there is an inspiratory effort
What is the Parafacial respiratory group (pFRG)?
A group of neuron in the ventral respiratory group important for generation rhythmic excitatory active expiratory rhythmic activity that excites expiratory muscles
What would happen if the Parafacial neurons did not have any influence from higher levels of the brain or the peripheral chemoreceptors?
There would be no change in tidal volume or respiration frequency
What kind of changes must neuronal networks adjust to for breathing?
- Metabolic demands
- Varying mechanical conditions (posture changes)
- Non-ventilatory behaviors (speaking, sniffing, eating)
- Pulmonary and non-pulmonary diseases
Where is the Rhythm of breathing generated?
In the ventral respiratory group (VRG) in the medulla
What neurotransmitters influence neural control of breathing?
•5-HT (serotonin)
•NE peptides
•Glutamate
Orexin
What is meant by volitional suprapontine influences?
Voluntary changes in breathing when you are talking and for example want to take a big breath
What happens once breathing is generated at the level of the ventral respiratory group by the activity of the PreBötzinger complex and the parafacial respiratory group?
The excitatory drive moves down the neuron pathways and activates respiratory muscles
What is rhythmic activity influenced by?
Sensory and neuromodulatory inputs originating from different regions within and outside the CNS
What is the pathway to excite the Diaphragm and Ext. Intercostal muscles for inspiration?
The PreBötzinger complex excites INS premotor neurons in the rostral VRG. This then excites phrenic and thoracic motor neurons in the cervical and thoracic spinal cord which excites the diaphragm and the external intercostals
What is the pathway to excite the tongue and upper airway muscles for inspiration?
The PreBötzinger complex excite the premotor neurons in the Rostral VRG and parahypoglossal region PXII. They then excite cranial motor neurons in the medulla which excite the tongue and upper airway
Which neurons are initially responsible for active expiration?
The pFRG neurons
What is the pathway for exciting the INT. Intercostal and abdominal muscles for active expiration?
The pFRG excite EXP premotor neurons (caudal VRG) which excite thoracic and lumbar motor neurons in the spinal cord which excite the INT. Intercostal and abdominal muscles
