Respiratory Control Flashcards
respiratory center
group of neurons in the brainstem that contain central pattern generators which generate rhythmic neural impulses to regulate respiration
how does the respiratory center receive information from the rest of the body
feedback loops
RC sends signals to effectors –> changes arterial blood composition –> sensed by chemoreceptors –> signal back to RC
cerebral cortex
has the conscious ability to override respiratory center TEMPORARILY
limited capacity - only for communication and breath holds
function of chemoreceptors
sense changes in arterial blood gas
speed and sensitivity/signal varies by type
central chemoreceptors
MAJOR control mechanism located in the ventral medulla (inside BBB)
signal for central chemoreceptors
PaCO2
causes changes in the pH of CSF
why does arterial pH not influence CSF pH
because H+ cannot cross BBB but CO2 can –> changes in arterial CO2 cause changes in CSF pH
effect of central chemoreceptors
if PaCO2 is high –> increases CSF H+ (decreases pH) –> stimulates an increase in ventilation to decrease PaCO2
if PaCO2 is low –> decreases CSF H+ –> increases pH –> stimulates a decrease In ventilation to increase PaCO2
is the response from central chemoreceptors fast or slow
slow
peripheral chemoreceptors
FINE TUNING mechanism of control located in carotid (and aortic) bodies
does NOT regulate in health - only if severely hypoxemic
signal for peripheral chemoreceptors
PaO2 (major)
PaCO2, pHa (minor)
only responds when PaO2 < 60 mmHg
effect of peripheral chemoreceptors
low PaO2 –> increase ventilation –> increase PaO2
high PaO2 –> decrease ventilation –> decrease PaO2
MINOR role in response to changes in PaCO2 or pHa
how does the presence of multiple stimuli (PaO2, PaCO2, pHa) effect response of chemoreceptors
more stimuli = stronger and faster response
what is the main respiratory stimulus
PaCO2
BOTH central and peripheral respond to PaCO2
apenic threshold
severely low PaCO2 will stop respiratory drive –> apnea
