Q****************Pc02 - super99

[ArchivalUser]

An anxiety-induced hyperventilation can often be successfully treated by the individual rebreathing the expired air from a paper bag held over the mouth region. Rebreathing this air can increase arterial Pc02
toward the normal range. Which of the following is the mechanism by which the increased Pc02 would first be detected?
A. Central chemoreceptors responding directly to the increased arterial Pco2
B. Central chemoreceptors responding to increases in cerebrospinal Pco2
C.Increased cerebral blood flow increasing the diffusion gradient for C02 toward the central
chemoreceptors
D. Peripheral chemoreceptors responding directly to the increased arterial Pc02
E.Peripheral chemoreceptors responding directly to the increased systemic venous Pc02

[ArchivalUser]

B...

[ArchivalUser]

d?????????

[ArchivalUser]

D. Peripheral chemoreceptors responding directly to the increased arterial Pc02 and send information to the brainstem to modify the rate of respiration.

[ArchivalUser]

B>

the change of PH in plasma will not stimulate Central chemo R. because H will not diffuse into CSF....only CO2 diffuse into CSF>>>>>>>forms H and and make the chemoreceptors respond to the change.

[ArchivalUser]

peripheral chemo receptors contribute very little under normal conditions via p co2 ...
periph chemo receptors contribute much to breathing only when po2 goes very low...

[ArchivalUser]

ld go for D as the question asks what would be the "first" detection mechanism

[ArchivalUser]

.THE RIGHT ANSWER IS D

.

CO2 REACH THE PERIPHERAL CHEMORECEPTORS THEN DIFFUSION TO CSF >>>TO CENTRAL CHEMORECEPTORS

Peripheral chemoreceptors LOW SENSITIVITY TO CO2 BUT RAPID ACTION

Central chemoreceptors HIGHLY SENSITIVE TO CO2/H BUT SLOW ACTION

[ArchivalUser]

CUD U PLZ EXPLAIN HOW IT STOPS THE HYPERVENTILATION?