7. Respiratory Control Flashcards
what are the 4 resp centers in the brainstem?
Dorsal resp group
Ventral resp group
Pontine resp group
Botzinger Complex
what is the Pre-Botzinger Complex
located btn rostral end of VRG and BotC
-critical for generation of resp rhythm = core rhythm
where is the DRG located
close to midline, around CN X & XII
part of the nucleus tractus solitarius
what is generated at the pre-BotC
timing (freq) of resp rhythm –> turn on/off inspiration
esp in babies
what is important in determining the resp freq
transition from inspiration to expiration (& vice versa)
what is apneusis
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
what happens if you lesion the PRG
apneusis
lose ability to turn off inspiration w/o additiona sensory info from CN X
what determines the timing of respiration
pre-BotC - core rhythm
& PRG - modify insp timing (turns it off)
what determines the pattern of breathing
DRG & VRG
what does DRG do
premotor to phrenic
receive lots of sensory info & generat pattern appropriate to circumstances
what is the fxn of VRG
rostral end: premotor phrenic –> inspiratory Ms
caudal end: premotor to upper airway –> Ms of expiration
expiration is passive, so why do you need expiratory Ms
passive expiration = diaphragm and abd Ms
active = in upper airway to maintain patency of airway
what is apnea
absence of resp effort (no inspiration)
from medullary or spinal damage
- increase CO2 and decrease O2- death if not supported
what is chemosensitivity
ability of certain chem to change the discharge rate of sensitive neurons
(O2, CO2 and H)
what would cause increased firing of chemorecepotors
increased CO2
increased H+
or decreased O2
why are chemoreceptors needed during hypoxia
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)
what happen to
How are central chemoreceptors activated?
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
What are peripheral chemoreceptors & what are its fxns?
-carotid body & aortic arch
Sensitive to O2, CO2 and H+ —> acute changes in blood gases
What are slowly adapting pul stretch receptors (SAR)?
Located in airway
Sensitive to stretch (directly proportional to lung vol)
==> inhibit inspiration & prolong expiration
In what cases are slowly adapting pul stretch receptor the most imp?
Infants - determine depth and rate - need to transition from state in womb to breathing- needed at all times
Adults during exercise (increase Vt)
What are rapidly adapting pul stretch receptors (RAR)?
Located in airway
Sensitive to irritation, foreign bodies & stretch
Effect = COUGH - try to get rid of irritant
What are J (juxtacapillary) receptors
Located near blood vessels of alveoli
Sensitive to Pul Edema
==> cough and tachypnea
How do SAR, RAR & J receptors travel to brain?
Fiber travel in vagus N
