Block 2b Regulation of Respiration

Question 1

Where is the respiratory center located?

Answer 1

nucleus of the tractus solitarious (NTS) of medulla oblongata / pons

Question 2

How is the respiratory center innervated?

Answer 2

vagal & glossopharyngeal nerves

Question 3

Dorsal Respiratory Group

Answer 3

part of the respiratory center that is responsible for inspiration

Question 4

pneumotaxic center

Answer 4

part of the respiratory center that limits inspiration

Question 5

Ventral Respiratory Group

Answer 5

part of the respiratory center that supplements the DRG as an overdrive mechanism for increased expiration & inspiration

Question 6

What is the Hering-Breuer Reflex?

Answer 6

chemo and stretch receptors via vagus nerve prevent overstretching

Question 7

What receptors serve as sensors for respiratory center innervation?

Answer 7

peripheral chemoreceptors, baroreceptors, mechano & chemo receptors in lung

Question 8

What is the dominant regulator of quiet breathing?

Answer 8

DRG

Question 9

In what range can pneumotaxic center limit inspiration?

Answer 9

3-40 breaths/min

Question 10

How does the VRG supplement the DRG in hyperventilation?

Answer 10

sends signals to abdominal muscles

Question 11

Where does chemical control of respiration occur?

Answer 11

at the chemosensitive area of the respiratory center to stimulate DRG

Question 12

What is the major chemoregulator of respiration?

Answer 12

CO2

Question 13

Why is blood H+ not such a great chemoregulator of respiration?

Answer 13

cannot diffuse across BBB

Question 14

How does blood O2 affect respiration?

Answer 14

via peripheral signaling only when PO2 < 60 mmHg

Question 15

Where are the chemoreceptors for O2?

Answer 15

carotid bodies & aortic bodies

Question 16

What are the 2 types of sleep apnea?

Answer 16

airway obstruction & central

Question 17

How is central sleep apnea caused?

Answer 17

by neural depression of the respiratory center

Question 18

How airway obstruction sleep apnea caused?

Answer 18

congenital or obesity

Question 19

What causes respiratory depression?

Answer 19

brain edema (inactivation of respiratory center) & anesthesia

Question 20

What can cause Cheyne-Stokes breathing?

Answer 20

heart failure (lag time for gas diffusion) & brain damage (inactivated DRG suddenly activates with great force, cycle repeats)

Question 21

What does the DRG do?

Answer 21

generates AP’s of increasing frequency to give slow, steady lung filling & regulation of inflation rate/max capacity

Question 22

How does the pneumotaxic center work?

Answer 22

terminates ramp signal of the DRG

Question 23

Describe the effect of CO2 on chemoregulation of respiration.

Answer 23

potent acute effect for 2-3 days, then weak chronic effect due to kidney regulation (increase HCO3, which eventually diffuses across BBB)

Question 24

What factors increase sensitivity of chemosensitive center to CO2?

Answer 24

increased H+ or decreased CO2 by causeing increased alveolar ventilation

Question 25

How does CO2 stimulate the chemosensitive area?

Answer 25

1) mainly H+ via CA, 2) modest direct effect of CO2

Question 26

Why is CO2 the main chemical regulator of respiration?

Answer 26

freely diffuses across BBB