4-Regulation of Respiration Flashcards
intrinsic neural control
og @ pons and medulla
-sends efferent impulses to respir muscles
also cerebral cortex for voluntary control
ventral respiratory group
VRG
neurons are inspiratory and expiratory
-esp powerful signals during active expir for abdom muscles
@medulla bilaterally
pre-botzinger complex
PBC
central pattern generator for rhythm of breathing
@VRG
-innvervates inspriatory neurons in VRG and DRG
dorsal respiratory group
DRG
mainly inspiratoyr
@dorsal medulla in nucleus tractus solitatrius
recieve input from pre-botz
pontine respir group
transmit inhib signals to inspir neurons of DRG
-limit inspiration
metabolic acidosis
dec HCO3/bicarb
requires dec PCO2 to keep pH the same
-inc alveolar vent
metabolic alkalosis
inc bicarb so inc PCO2 to keep pH
-dec alveolar vent
respiratory avidosis
inc PCO2
-acute resp = small inc bicarb bc kidneys respond slowly
-chronic = large inc bicarb, pH normalized
not breathing enough, hypoventilatin
respiratory alkalosis
dec PCO2
-acute = small dec bicarb bc kidneys slow
-chronic = large dec bicarb, pH normalized
hyperventilation
pH =
bicarb/ pCO2
CO2 chemoreceptors
high CO2 = inc ventilation bc stim chemoreceptors (central and peripheral)
low pH only affets peripheral chemos, inc vent
apneic threshold
hold breath longer bc driven PCO2 below apneic threshold
hyperventilation drives down PaCO2 so drive to breathe is reduced
central chemoreceptors
brain nuclei (spread throughout, multi) sensitive to CO2/H+
CO2 readily diffuses across BBB but not H+
CO2 causes inc H+ in CSF
peripheral chemoreceptors
as PO2 dec = inc alveolar ventilation
aortic body chemorecptors + carotid body (main type II glomus cells)
-sens to O2 tension reductions so inc respir and BP
hyoxia inhibits
K+ channels so depolarize and Ca influx
synergistic effect of periperal chemo
steeper slope = greater inc inalveolar vent for given inc in PCO2
lower PO2 + lower pH enhance vent resp to incs in PCO2
sensory integration site
tractus solitarius has vagal and glossopharyngeal nerves that transmit sensory signals into respir center
-peripheral chemos + baroreceptors + lungs
central command
during strenuous exercise O2 consumption and CO2 formation inc
stable arterial pressures and pH bc brain transmits to excite respir (feedforward signals to inc vent)
signals from higher brain centers modulated by
- input from peripheral chemoreceptors
- type III and IV muscle afferents are sensitive to stretch and metabolites (from muscle contraction)
airway irritant receptors
@ epi of trachea, bornchi, bronchioles
-coughing and sneezing + bronchoconstriction and inc mucus production
pulmonary juxtacapillary receptors
sensory nerve endings in alveolar walls
-engorge of capillaries with blood from congestion or edema = apnea > tachypnea, bradycardia, hypotension, feeling dyspnea
kussmaul breathing
diabetic ketoacidosis (metabolic acidosis)
super low pH drives fast, deep breaths
biot’s breathing
ataxic, shallow irregular apnea
-brain stem injury or stroke
obstructive sleep apnea
-upper airway collapse during sleep = surges in neural activity
poor notcuranl sleep quality + ensuing daytime fatigue + cog dysfunction
-risk factor for systemic hypertension, cardio dz, stroke, abnormal glucose metabolism
risk factor for sleep apnea
age, male, obesity, family hx, menopause, craniofacial abnormalities
