7. Respiratory Control

Question 1

what are the 4 resp centers in the brainstem?

Answer 1

Dorsal resp group

Ventral resp group

Pontine resp group

Botzinger Complex

Question 2

what is the Pre-Botzinger Complex

Answer 2

located btn rostral end of VRG and BotC

-critical for generation of resp rhythm = core rhythm

Question 3

where is the DRG located

Answer 3

close to midline, around CN X & XII

part of the nucleus tractus solitarius

Question 4

what is generated at the pre-BotC

Answer 4

timing (freq) of resp rhythm –> turn on/off inspiration

esp in babies

Question 5

what is important in determining the resp freq

Answer 5

transition from inspiration to expiration (& vice versa)

Question 6

what is apneusis

Answer 6

failure to turn inspiration off

(can be observed with lesion of PRG - aka pontine damage)

slight delay but then increase CO2 and decrease O2 - death if not supported

Question 7

what happens if you lesion the PRG

Answer 7

apneusis

lose ability to turn off inspiration w/o additiona sensory info from CN X

Question 8

what determines the timing of respiration

Answer 8

pre-BotC - core rhythm

& PRG - modify insp timing (turns it off)

Question 9

what determines the pattern of breathing

Answer 9

DRG & VRG

Question 10

what does DRG do

Answer 10

premotor to phrenic

receive lots of sensory info & generat pattern appropriate to circumstances

Question 11

what is the fxn of VRG

Answer 11

rostral end: premotor phrenic –> inspiratory Ms

caudal end: premotor to upper airway –> Ms of expiration

Question 12

expiration is passive, so why do you need expiratory Ms

Answer 12

passive expiration = diaphragm and abd Ms

active = in upper airway to maintain patency of airway

Question 13

what is apnea

Answer 13

absence of resp effort (no inspiration)

from medullary or spinal damage

• increase CO2 and decrease O2- death if not supported

Question 14

what is chemosensitivity

Answer 14

ability of certain chem to change the discharge rate of sensitive neurons

(O2, CO2 and H)

Question 15

what would cause increased firing of chemorecepotors

Answer 15

increased CO2

increased H+

or decreased O2

Question 16

why are chemoreceptors needed during hypoxia

Answer 16

in hypoxia -normal resp neurons shut down and make the problem worse

• so need chemoreceptors to prevent breathing from shutting down

(increase firing bc O2 is low and CO2 & H is high)

Question 17

what happen to

Question 18

How are central chemoreceptors activated?

Answer 18

Located on ventral surface of medulla

Sensitive (indirectly) to CO2 in blood

—> CO2 cross BBB —> carbonic anhydrase makes H2CO3 —> reduce to H+ & HCO3- —> H + activate central chemoreceptors –> signal DRG & VRG

-make you breathe regularly

Question 19

What are peripheral chemoreceptors & what are its fxns?

Answer 19

-carotid body & aortic arch

Sensitive to O2, CO2 and H+ —> acute changes in blood gases

Question 20

What are slowly adapting pul stretch receptors (SAR)?

Answer 20

Located in airway

Sensitive to stretch (directly proportional to lung vol)

==> inhibit inspiration & prolong expiration

Question 21

In what cases are slowly adapting pul stretch receptor the most imp?

Answer 21

Infants - determine depth and rate - need to transition from state in womb to breathing- needed at all times

Adults during exercise (increase Vt)

Question 22

What are rapidly adapting pul stretch receptors (RAR)?

Answer 22

Located in airway

Sensitive to irritation, foreign bodies & stretch

Effect = COUGH - try to get rid of irritant

Question 23

What are J (juxtacapillary) receptors

Answer 23

Located near blood vessels of alveoli

Sensitive to Pul Edema

==> cough and tachypnea

Question 24

How do SAR, RAR & J receptors travel to brain?

Answer 24

Fiber travel in vagus N

Question 25

RAR and J receptors are important for survival b/c…

Answer 25

They mediate protective reflexes that OVERRIDE the normal resp control systems

Question 26

How and when do cortical influences control breathing?

Answer 26

Bypass the medullary centers and send input directly to Ms of resp via phrenic N

Controlled during talking, holding breath, etc