Control of Ventilation: Central Chemorecptors Flashcards Preview

Apex 1 - 2 Respiratory II: Physiology (24) > Control of Ventilation: Central Chemorecptors > Flashcards

Flashcards in Control of Ventilation: Central Chemorecptors Deck (31)
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1

The central chemoreceptors are located just a few microns below the surface of the anterolateral aspect of the

Medulla

2

The central chemoreceptors are located just a few microns below the surface of the anterolateral aspect of the medulla. This region sends stimulatory impulses to the

A. Dorsal respiratory center

B. Ventral respiratory center

Dorsal respiratory center

3

Central chemoreceptor primarily responds to

A. PaO2

B. PaC02

PaC02

4

Peripheral chemoreceptors primarily respond to

A. PaO2

B. PaC02

PaO2

5

The highly selective barrier that separates the blood from the CSF is called:

Blood-brain-barrier (BBB)

6

The following freely diffuse across the BBB

A. Some gases and lipid-soluble molecules

B. ions, glucose, and amino acids

Some gases and lipid-soluble molecules freely  diffuse across the BBB

7

The following are carried across the BBB via active transport mechanisms

A. Some gases and lipid-soluble molecules

B. ions, glucose, and amino acids

Ions, glucose, and amino acids

8

Which freely diffuses through the BBB

A. CO2

B. H+ and HC03-

CO2

9

Which do(es) not diffuse through the BBB

A. CO2

B. H+ and HC03-

H+ and HC03-

10

After it crosses the BBB, how does CO2 react?

 

CO2 + H2O H2CO3 HCO3- + H+

CO2 reacts with carbonic anhydrase and dissociates into H+ and HCO3-

(Just like it does inside the erythrocyte)

11

The concentration of which ion in the CSF is the most important stimulus for the central chemoreceptor?

H+

12

Which ion drives the respiratory pacemaker in the dorsal respiratory center?

H+

13

How does the rise of H+ affect the rate and depth of respiration?

 

Increases rate and depth of respiration

(until a new steady-state for Ve is achieved)

14

An acute rise in PaCO2 leads to

A. Increased [H+] in the CSF and increases Ve

B. Decreased [H+] in the CSF and decreases Ve

Increased [H+] in the CSF and increases Ve

15

An acute decline in PaCO2 leads to

A. Increased [H+] in the CSF and increases Ve

B. Decreased [H+] in the CSF and decreases Ve

Decreased [H+] in the CSF and decreases Ve

16

An acute rise in PaCO2 Increased [H+] in the CSF and increases Ve.

An acute decline in PaC02  Decreased [H+] in the CSF and decreases Ve.

These changes occur within which time frame?

minutes

17

An acute rise in PaCO2 Increased [H+] in the CSF and increases Ve.

An acute decline in PaC02  Decreased [H+] in the CSF and decreases Ve.

These changes occur within minutes and provide precise control of

blood gas tensions

18

True or False

Non-volatile acids do not pass through the BBB

True

Non-volatile acids do not pass through the BBB

19

Non-volatile acids don't influence Ve on a short-term basis. Why is that?

They Do not pass through the BBB

20

True or False

Non-volatile acids do influence Ve on a longer-term basis.

True

Non-volatile acids do influence Ve on a longer-term basis.

21

HC03- equilibrates between the blood and the CSF - this process begins after.

a few hours

22

HC03- equilibrates between the blood and the CSF - this process begins after a few hours and peaks at

~ 2 days

23

HC03- equilibrates between the blood and the CSF - this process begins after a few hours and peaks at ~ 2 days

Therefore, the effect of hyperventilation on PaC02 is limited to

this window of time

24

After equilibration occurs, the pH of the CSF is restored to normal (pH 7.32) as a result of the active transport of ---- from the plasma to the CSF

HC03-

25

The central chemoreceptor is stimulated by hypercarbia and hypoxemia, however, it is depressed by which type of hypercarbia and hypoxemia?

Profound hypercarbia and hypoxemia

26

The central chemoreceptor is located on the

A. Dorsal surface of the medulla

B. Ventral surface of the medulla

Ventral surface of the medulla

27

The central chemoreceptor responds to

A. PaCO2

B. PaO2

PaCO2

28

The central chemoreceptor is stimulated by 

A. the pH of the blood

B. the pH of the CSF

the pH of the CSF

29

Why HC03- in the plasma does not acutely affect the central chemoreceptor?

Does not freely diffuse across the BBB

30

If serum HC03- rises, how long does it take for the CSF pH to equilibrate?

Hours to days