Control of Ventilation Flashcards
How is respiratory rhythm at rest maintained?
Inspiratory neurons are activated for a short period, in what is thought to be a rapid positive feedback loop. Their activity then shuts off, and passive expiration takes place due to the elastic recoil of the lung
Basal activity in the inspiratory muscles during inspiration is directed towards the larynx, pharynx and tongue to maintain airway patency.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/333/575/612/a_image_thumb.png?1611188714)
Where are peripheral chemoreceptors found?
Aortic and carotid bodies
![](https://s3.amazonaws.com/brainscape-prod/system/cm/333/575/613/a_image_thumb.png?1611188714)
What are the different types of chemoreceptors involved in modulating respiratory effort?
- Central chemoreceptors
- Peripheral chemoreceptors
What is the downstream effect of peripheral chemoreceptor activation?
Stimulus inactivates K+ channels, causing the receptor cell to depolarise and send signals to the medullary centres to increase ventilation
![](https://s3.amazonaws.com/brainscape-prod/system/cm/333/575/614/a_image_thumb.png?1611188715)
What are peripheral chemoreceptors sensitive to?
Decreases in:
- PO2
- pH
Increases in:
- PCO2
What is the ventilatory response if the system becomes alkalotic?
Ventilation will be inhibited, causing the body to retain CO2 and thus increase H+ concentration
![](https://s3.amazonaws.com/brainscape-prod/system/cm/333/575/615/a_image_thumb.png?1611188715)
What acts to control changes in ventilatory response to changes in PO2 or PCO2?
Increase in PO2 and decrease in PCO2 act as negative feedback for the response system
![](https://s3.amazonaws.com/brainscape-prod/system/cm/333/575/616/a_image_thumb.png?1611188715)
What stimulates central chemoreceptors?
H+ in the CSF
![](https://s3.amazonaws.com/brainscape-prod/system/cm/333/575/617/a_image_thumb.png?1611188716)
How low does PO2 have to fall for peripheral chemoreceptors to be stimulated?
<60 mmHg
How does CO2 go from being in the arterial circulation to stimulating central chemoreceptors as H+ ions?
It crosses into the cerebrospinal fluid, where it is combined with H2O by carbonic anhydrase to carbonic acid, where it then dissociates to H+ and HCO3-. H+ ions then stimulate central chemoreceptors
![](https://s3.amazonaws.com/brainscape-prod/system/cm/333/575/618/a_image_thumb.png?1611188716)
What is the response to decreased pH or increased PCO2?
These both stimulate ventilation in response to the system becoming acidotic. This blows off CO2, resulting in a decrease in H+ ions.
Where are central chemoreceptors found?
Located in the medulla
Of peripheral and central chemoreceptors, which is regarded as being the primary ventilatory drive mechanism?
Central chemoreceptors
Of peripheral and central chemoreceptors, which is regarded as being the secondary ventilatory drive mechanism?
Peripheral chemoreceptors
Under what circumstances would stimulation of central chemoreceptors result in normal respiration?
Chronic stimulation of central chemoreceptors e.g. in COPD