Pulmonary Lecture 6 Flashcards
Where is the respiratory sensor in the brain?
The medulla
Once the medulla receives inputs how does it respond?
It tells motor neurons that control the respiratory system to adjust
Change in tidal volume or breathing rate
What is a peripheral chemoreceptor
A receptor located out in the blood stream that senses particular compounds.
3 classes
What are Peripheral chemoreceptors in carotid bodies
clusters of neurons located in the carotid artery.
Mediate increase in ventilation in response to:
- low arterial oxygen
- high arterial CO2
- High Arterial Protons [H+]
How does the body compensate for the lower levels of PCO2 in Denver
the kidneys compensate by decreasing HCO3 levels
When Arterial Oxygen Pressure decreases how does Ventilation respond
It increases in an exponential fashion
what is the response to a high arterial CO2 from the carotid bodies
it occurs very fast (in seconds) to maintain pH
What is the only mediator of response to Metabolic Alkalosis or Acidosis
High Arterial Protons [H+] - fast response
Where are central chemoreceptors located?
On the ventral surface of the medulla
What are properties of central chemoreceptors?
Bind protons in CSF but sense Arterial CO2
Response is slow (minutes)
Mediates 80% of ventilatory response when there is a long term high Pressure of CO2
How does a high proton concentration effect ventilation
It increases it
What receptor type would be more prevalent when climbing mount everest?
Peripheral O2 Receptors
Response to high altitude:
Decrease in PIO2 –> Decrease in PaO2 –> Activation of Peripheral O2 Receptors –> Increase in Ventilation –> Increase in PaO2
This response will cause a negative feedback that decreases PCO2
How does High Altitude effect PCO2
It will cause a drop of CO2 in the CSF thus decreasing protons which decreases the drive for increased ventilation
Describe the negative feedback look of Increased Ventilation on CO2
Decrease CO2 –> Decreased CSF CO2 –> Decreased CSF H+ –> Decreased activation of Central H+ Receptor –> Decreased ventilation
T/F the initial recovery of PaO2 at high altitudes in incomplete
True - Due to CO2 feedback loop (compensation will take 2-3 days due to decrease in HCO3
