Control of Respiration Flashcards
Where is the respiratory center in the brain?
The medulla
Where are peripheral chemoreceptors located?
Carotid bodies
Peripheral chemoreceptors increase ventilation in response to three things: ____________.
low arterial oxygen, high arterial P(CO2), or high arterial [H+]
Control of respiration through low arterial oxygen is relatively insensitive until _________.
arterial oxygen decreases to
Where are the central chemoreceptors located?
On the ventral surface of the medulla
The central chemoreceptors have ______ receptors.
[H+]
Protons do not cross the blood-brain barrier to touch the medulla, rather _________.
CO2 diffuses into the CSF and converts to carbonic acid
The sensing of protons is relatively ________ in the central chemoreceptor system (unlike the peripheral system).
slow, because the CSF does not have carbonic anhydrase
The proton sensor on the medulla controls about ______ percent of the ventilatory response to chronically high P(CO2).
80
Which ventilatory response kicks in under conditions of low oxygen pressure?
Peripheral oxygen receptors (in the carotid bodies)
Which ventilatory response kicks in under conditions of rapidly increased CO2?
Peripheral CO2 receptors
Which ventilatory response kicks in under conditions of metabolic acid/base insults?
Peripheral proton receptors
Which ventilatory response kicks in under conditions of chronically high CO2 levels?
Central chemoreceptors
The __________ is the most important day-to-day regulator of ventilation.
medullary chemoreceptor system
The ______ response in exercise is controlled by CO2, while the _____ response is controlled by protons.
early/moderate; late/extreme
The _________ generates breathing without input from other areas.
medulla
There are both P(O2) and P(CO2) sensors in the aortic arch and carotid bodies, but [H+] sensors are only in the ________.
carotid bodies
The only pH detector that can modulate ventilation is _____.
the carotid bodies
Describe the integrated response to high altitude.
The initial drop in Pa(O2) stimulates the peripheral O2 receptors to increase the ventilation rate. The increased ventilation rate lowers the P(CO2), which raises the pH of the CSF and causes the medulla to limit the ventilation rate. Excretion of HCO3- by the kidneys reduces the CSF’s pH and allows the ventilation to increase beyond its first levels.
