5.5 Regulation of Respiration Flashcards
What is meant by neurogenic regulation?
Regulation that arises from the nervous system
Which phases of the respiratory cycle do the ventral/dorsal respiratory groups in the medulla control?
Dorsal: Inspiration
Ventral: Inspiration and Expiration
By which pathways do the dorsal and ventral respiratory groups exert a motor effect?
Respiratory motor pathways
Structure/function of dorsal respiratory group (DRG)
Inspiratory neurons responsible for timing of the respiratory cycle
Structure/function of the ventral respiratory group (VRG)
Neurons that influence both inspiration and expiration
Which two centres are located within the pontine respiratory centre?
- Pneumotaxic centre
- Apneustic centre
Role of pneumotaxic centre
Limit depth of breathing
Role of apneustic centre
Delay inspiratory off-switch
What is apneusis?
a disturbance of respiratory rhythm characterized by severely prolonged inspiratory effort
Are the same neurons active at all points in the respiratory cycle?
- No
- Different neurons are activated at different points in the respiratory cycle, creating a repeating pattern of neuronal activation
Describe the location and action of slow-acting stretch receptors in the respiratory system
- Predominantly in airways
- Act as lung volume sensor
Describe the location and action of rapid-acting receptors in the respiratory system
- Located in superficial mucosal layer
- Stimulated by changes in tidal volume, breathing frequency, and compliance of the lungs
Describe the location and role of vagal c-fibre nociceptors in the respiratory system
- Located in pulmonary capillaries and bronchi
- Sensitive to inflammation, irritants etc.
List some circumstances under which PCO2 of CSF would be expected to increase
- Hypoventilation
- Exertion
What has a bigger impact on alveolar ventilation: pH or PCO2?
PCO2
Where are peripheral chemoreceptors located? Why is this easy to remember?
- They are located in the carotid bodies and aortic arch
- These are the same locations as the baroreceptors
What are peripheral chemoreceptors sensitive to?
- Primarily oxygen
- Also somewhat to CO2 and H+
By what nerve do carotid chemoreceptors send information to the dorsal respiratory area?
Glossopharyngeal nerve
By what nerve do aortic chemoreceptors send information to the dorsal respiratory area?
Vagal nerve
Describe the increase in alveolar ventilation as partial pressure of oxygen decreases. Why does this make sense.
- Exponential
- Think back to the haemoglobin saturation/PO2 graph; it increases exponentially, then levels out. As the level of oxygen dips below the plateau of haemoglobin saturation, this is when alveolar ventilation begins to increase dramatically.
When O2, CO2, and H+ all change at once, how does this influence the change in alveolar ventilation?
It magnifies it
Relate respiratory acidosis and respiratory alkalosis to hyperventilation and hypoventilation
Acidosis: Hypoventilation, too much CO2, too much H+, too acidic
Alkalosis: Hyperventilation, not enough CO2, not enough H+, too basic
What is hyperpnea?
Increased breathing rate
What is the first point at which motor movement stimulates an increase in breathing?
As an efferent motor signal travels out of the brain towards peripheral muscles, it passes the medulla, and stimulates an increase in breathing on the way down.
How do muscles feed back to the respiratory centre to control ventilation?
- Proprioceptors in muscle detect metabolic activity and mechanical stretch of muscle, helping to inform changes in respiratory rate
What are the C-fibres in the pulmonary capillaries and bronchi also called?
Juxtacapillary receptors
