Neuroanatomy of Breathing

Question 1

What nerves give peripheral chemoreceptor feedback?

Answer 1

hypoglossal
laryngeal
carotid sinus

Question 2

What nerve regulates breathing frequency and volume?

Answer 2

vagus

Question 3

What nerves control respiratory muscles?

Answer 3

intercostals

Question 4

What nerve controls diaphragm inspiration?

Answer 4

phrenic

Question 5

What are the inspiratory muscles?

Answer 5

sternocleidomastoid
scalenes
external intercostals
parasternal intercostals
diaphragm

Question 6

What are the expiratory muscles?

Answer 6

internal intercostals
external abdominal oblique
internal abdominal oblique
transverse abdominals
rectus abdominis

Question 7

How do the abdominal wall muscles aid in expiration?

Answer 7

push gut up against diaphragm

Question 8

what are the cranial motorneurons important for?

Answer 8

opening and closing the glottis, affecting upper airway diameter and nostril flaring

Question 9

Where is the central pattern generator?

Answer 9

the pons and the medulla

Question 10

What is contained within the pons respiratory center?

Answer 10

pneumotaxic center

apeustic center

Question 11

What is followed before the medulla?

Answer 11

the pre-botzinger complex

Question 12

What is found in the medullary respiratory center?

Answer 12

dorsal respiratory group

ventral respiratory group

Question 13

What is the dorsal respiratory group involved with?

Answer 13

inspiration

Question 14

What is the ventral respiratory group involved with?

Answer 14

inspiration and expiration at the top and bottom

Question 15

Where is the dorsal respiratory group found?

Answer 15

in the nucleus tractus solitarius

Question 16

What is the dorsa respiratory group the site of?

Answer 16

sensory input

central chemoreceptor input

Question 17

What are the three regions of the ventral respiratory group?

Answer 17

rostral
intermediate
caudal

Question 18

What is contained in the rostral region?

Answer 18

nucleus retrofacialis - expiration

Question 19

What is contained within the intermediate region?

Answer 19

Pre-botzinger and the nucleus ambiguus, nucleus para-ambigualis - inspiration

Question 20

What is the pre-botzinger though to be?

Answer 20

the respiratory pattern generator

Question 21

What is contained within the caudal region?

Answer 21

the nucleus retroambigualis - expiration

Question 22

What happens to breathing when sections above the pons?

Answer 22

normal when vagus intact

slow and deep when vagus cut

Question 23

What happens to breathing when superior pons is cut?

Answer 23

slow and deep breathing with vagus intact

apneusis when vagus cut

Question 24

What happens when all the pons is cut?

Answer 24

irregular rhythm with vagus intact

irregular and infrequent rhythm when vagus cut

Question 25

What happens when the pons and medulla are cut?

Answer 25

apnea

Question 26

What tells us that there is a heirachy of neural inputs into control of breathing?

Answer 26

sectioning of brain stem with vagus intact produces a decrease in breathing depth and frequency

Question 27

What tells us there are neural feeback loops controlling frequency, rhythmicity and depth?

Answer 27

cutting the vagus nerve produces a variety of effects on the heirarchy

Question 28

What tells us there are feedback interactions between several nerves which contribute inter-dependently to breathing pattern?

Answer 28

the varied effects of cutting the vagus can only be explained by input from other neural networks

Question 29

What is a respiratory rhythm generator?

Answer 29

a network of interneurons that produce a predictable and repetitive motor pattern

Question 30

What are the properties of an RRG?

Answer 30

always active even in the absence of conscious input Transmit in an orderly sequence Response to inputs from other parts of the brain as well as sensory afferents

Question 31

What are the 3 phases of the breathing cycle?

Answer 31

inspiration post-inspiration late-expiration

Question 32

What are the 6 types of neuronal discharge?

Answer 32

``` pre-I early -I I Late-I early -E E ```

Question 33

What does Pre-I do?

Answer 33

inhibits expiratory neural circuit and causes expiratory muscles to relax

Question 34

What does Early-I do?

Answer 34

inhibits output from entire RRG causing a refractory period

Question 35

What does I do?

Answer 35

ramp fire increasing frequency and recruiting more I neurons - inhibit E and pre-I - inspiratory muscles contract and exp muscles relax

Question 36

What does Late-I do?

Answer 36

feed back to suppress I signalling which may involve stretch receptor input from vagus - insp muscles relax and lung begins to deflate due to elastic recoil

Question 37

What does Early E do?

Answer 37

repress all I and E firing - creates refractory period at peak inhalation - lung deflates as insp muscles relax

Question 38

What does E do?

Answer 38

ramp fire and activate exp muscles...major conscious input into breathing - exp muscles contract as insp muscles relaxed

Question 39

What does RRG activity vary in relation to?

Answer 39

tidal volume air flow phrenic nerve activity