21.7 Neural Control of Ventilation

Question 1

The ________ chemoreceptors in the aortic and carotid bodies respond to the ________ of arterial blood.

Answer 1

The peripheral chemoreceptors in the aortic and carotid bodies respond to the partial pressure of oxygen of arterial blood.

Question 2

Where are the peripheral chemoreceptors located?

Answer 2

The peripheral chemoreceptors in the aortic and carotid bodies respond to the Po2Po2 of arterial blood.

Question 3

Where are the central chemoreceptors located?

Answer 3

medullary reticular formation

Question 4

Central chemoreceptors respond to what changes?

Answer 4

hydrogen ion concentration and partial pressure of carbon dioxide of the brain extracellular fluid
hydrogen ion concentration of CSF

Question 5

Groups of neurons in the medulla of the brainstem maintain eupnea:
The (1) ____________________ in the brainstem sets the basic pattern of ventilation.
These neurons are assisted by neurons in the (2)_________________ and the (3)____________ of the pons and medulla.

Match 1, 2, and 3 with:
A. dorsal respiratory group (DRG)
B. respiratory pattern generator (RPG)
C. ventral respiratory group (VRG)

Answer 5

Groups of neurons in the medulla of the brainstem maintain eupnea: The respiratory pattern generator (RPG) in the brainstem sets the basic pattern of ventilation. These neurons are assisted by neurons in the ventral respiratory group (VRG) and the dorsal respiratory group (DRG) of the pons and medulla.

Question 6

• If central chemorecptors detect:
  
  • an increase in partial pressure of CO2, they trigger _________ .
  • a decrease in partial pressure of CO2, they trigger _________.

Answer 6

• If central chemorecptors detect:
  
  • an increase in partial pressure of CO2, they trigger hyperventilation.
  • a decrease in partial pressure of CO2, they trigger hypoventilation.

Question 7

If central chemorecptors detect a/an ________ in partial pressure of CO2, they trigger hyperventilation.

Answer 7

an increase in partial pressure of CO2, they trigger hyperventilation.

Question 8

If central chemorecptors detect a/an _________ in partial pressure of CO2, they trigger hypoventilation.

Answer 8

a decrease in partial pressure of CO2, they trigger hypoventilation.

Question 9

Which of the following triggers hyperventilation?

a. high partial pressure of oxygen in arterial blood
b. low partial pressure of carbon dioxide in arterial blood
c. low concentration of hydrogen ions in arterial blood
d. high partial pressure of carbon dioxide in arterial blood

Answer 9

Which of the following triggers hyperventilation?

D. high partial pressure of carbon dioxide in arterial blood

Question 10

Peripheral chemoreceptors are most sensitive to __________.

a. concentration of hydrogen ions in cerebrospinal fluid
b. partial pressure of carbon dioxide in the blood
c. concentration of hydrogen ions in the blood
d. partial pressure of oxygen in arterial blood

Answer 10

Peripheral chemoreceptors are most sensitive to __________.

Answer: D. partial pressure of oxygen in arterial blood

Question 11

The most important stimulus that induces changes in ventilation is __________.

a. partial pressure of oxygen in systemic capillaries
b. partial pressure of oxygen in pulmonary capillaries
c. partial pressure of oxygen in venous blood
d. partial pressure of carbon dioxide in arterial blood

Answer 11

The most important stimulus that induces changes in ventilation is __________.

Answer: D. partial pressure of carbon dioxide in arterial blood

Question 12

What would increase the amount of oxygen unlaoaded by hemoglobin into peripheral tissues?

decreased temperature

decreased pH

decrased levels of BPG

decreased levels of PCO2

Answer 12

What would increase the amount of oxygen unlaoaded by hemoglobin into peripheral tissues?

decreased temperature

decreased pH

decrased levels of BPG

decreased levels of PCO2

Question 13

• High-altitude acclimatization – gradual increase in elevation b (rather than hours) allows climbers to tolerate much lower atmospheric oxygen levels
• Peripheral chemoreceptors stimulate increase in ventilation, permitting body to maintain acceptable blood PO2 levels
• Requires days because sensitivity of chemoreceptors for low PO2 increases with prolonged exposure; the longer they are exposed to low PO2, the more they stimulate increase in ventilation
• Allows experienced climbers to reach great elevations without supplemental oxygen

Question 14

•Do not forget that there is some voluntary control over ventilation supplied by ____________; can override or bypass respiratory centers

Answer 14

•Do not forget that there is some voluntary control over ventilation supplied by cerebral cortex; can override or bypass respiratory centers

Question 15

•Alterations of _______________ are most powerful stimuli to induce classic negative feedback loop responses from central chemoreceptors:

Answer 15

•Alterations of arterial PCO2 are most powerful stimuli to induce classic negative feedback loop responses from central chemoreceptors:

Question 16

–High PCO2 or H+ concentration (or both) triggers hyperventilation (Figure 21.28a); VRG is stimulated which increases ventilation rate; lowers CO2 and H+, restoring homeostasis

–Low PCO2 or H+ concentration (or both) triggers hypoventilation (Figure 21.28b); VRG is inhibited which decreases ventilation rate; increases CO2 and H+, restoring homeostasis