Lecture 25: Central Control of Respiration

Question 1

what is the primary regulator of ventilation?

Answer 1

PaCO2

Question 2

what are the ventilation control elements?

Answer 2

central controllers
effectors (resp muscles)
sensors (central and peripheral)

Question 3

what are the respiratory centers in the brainstem

Answer 3

medulla and pons

Question 4

what are the breathing rhythm generators

Answer 4

rostral ventromedial neurons (pre-Botzinger complex) in the medulla

Question 5

what are the inspiratory neurons of medulla

Answer 5

dorsal respiratory group

Question 6

what are both inspiratory and expiratory neurons in medulla

Answer 6

ventral respiratory group

Question 7

what two respiratory centers around found in the pons

Answer 7

pneumotaxic center (turns off inspiration of DRG)
Apneustic center (prolongs inspiration)

Question 8

when is the dorsal respiratory group of medulla active

Answer 8

during eupnea (reg breathing)
inspiratory neurons

Question 9

what does the dorsal respiratory group receive sensory input from

Answer 9

CN 9 and 10

Question 10

when is the ventral respiratory group active

Answer 10

during forced expiration

Question 11

what are the pontine centers

Answer 11

pneumotaxic center and apneustic center

Question 12

what is the role of the penumotaxic center

Answer 12

• turns off inspiration at the DRG
• limits tidal volume

Question 13

what is the role of the apneustic center

Answer 13

• apneusis = abnormal breathing pattern w/ prolonged inspiration

Question 14

what is the cortical control of respiration responsible for

Answer 14

voluntary control of vocalizations, sighing, breath holding, etc

Question 15

what is the limbic respiratory system responsible for

Answer 15

emotionally induced changes in ventilation

ex: fear

Question 16

what is hypothalamic respiratory control responsible for

Answer 16

temperature control
ex: fever

Question 17

what sensors are chemoreceptors, which are both chemo and mechanoreceptors

Answer 17

central sensors = chemoreceptors
peripheral sensors = chemo and mechanoreceptors

Question 18

where are central chemoreceptors located

Answer 18

ventral surface of medulla

Question 19

what stimulates central chemoreceptors

Answer 19

increased H+ in the CSF
H+ comes from CO2 diffusing across the BBB

Question 20

Decreasing PaO2 causes an increased sensitivity of ventilation to ?

Answer 20

PaCO2

Question 21

where are peripheral chemoreceptors found

Answer 21

carotid and aortic bodies

Question 22

what do peripheral chemoreceptors mainly respond to

Answer 22

changes in PaO2
- also respond to changes of H+ (acidosis stimulates ventilation)
- have a weak response to CO2

Question 23

what must PaO2 levels fall to before ventilation gets increased significantly

Answer 23

PaO2 must be below 60-70mmHg

Question 24

name of cells in carotid bodies that respond to hypoxia, hypercapnia and low pH (part of peripheral chemoreceptor)

Answer 24

Glomus cells

Question 25

what is the effect of activation of pulmonary stretch receptors (mechanosensitive receptors in airway smooth muscle)

Answer 25

inhibit further inspiration = Hering-Breuer reflex

Question 26

what respiratory receptors increase ventilation w/ limb movement

Answer 26

chest wall and proprioceptive receptors

Question 27

what is the effect of activation of irritant receptors

Answer 27

bronchoconstriction

Question 28

what activates J-receptors and what is the effect

Answer 28

activated by engorgement of pulmonary capillaries (ex. left sided heart failure)
- stimulates respiration

Question 29

what is the hypothesized ventilatory regulation response to exercise?

Answer 29

ventilation response to exercise is thought to be caused by impulses from the motor cortex