LESSON 13 - control of breathing during exercise Flashcards
what are the two terms used to describe an increase in ventilation ?
hypernea and hyperventilation
when do we experience hyperpnea ?
experience during moderate and heavy intensity exercise
when do we experience hyperventilation ?
experience diring servers intensity domain
what is hyperpnea ?
an increase in ventilation that is proportional to metabolic demands
what is hyperventilation ?
an increase in ventilation that exceeds metabolic demands
is it hyperpnea or hyperventilation that is an “increase in breathing rate but within your needs” ?
hyperpnea
is it hyperpnea or hyperventilation that is an increase in breathing but more than needed ?
hyperventilation
is it hyperpnea or hyperventilation that “blood gasses remain from normal” ?
hyperpnea
is it hyperpnea or hyperventilation that “blood gases deviate from normal” ?
hyperventilation
what does increase in muscle work mean for metabolism (ATP), VO2 and CO2, and Va and Ve ?
- increase in metabolism (ATP)
- increase in VO2 and CO2
- increase in Va and Ve
when are we utilizing more VO2 and producing more CO2 ?
during increased exercise / muscle work
why do we breath during exercise ?
- CO2 produced must be cleared
- O2 extracted by the muscles from blood must be replenished
why must CO2 produced be cleared during exercise ?
to prevent arterial PCO2 and H+ from rising
why must O2 extracted by the muscles from blood be replenished during exercise ?
to prevent arterial PO2 from falling
a rise in CO2 is associated with a rise in ___ ions or a __________ in pH levels (acidosis)
- H+
- reduction
what happens if there is too much H+ ions or CO2 ?
becomes more acidic / acidosis
PaO2 ≈ (approx. equal to) Va / O2
replenish oxygen
PaCO2 ≈ (approx. equal to) CO2 / Va
prevent CO2 retention
Which of PaCO2 or PaO2 should be regulated most tightly ?
PaCO2
why should PaCO2 be tightly regulated over PaO2 ?
large changes in PaO2 at lungs dont effect O2 saturation drastically, but even small changes in PaCO2 can greatly impact pH
can the body handle acidosis well ?
no, it doesnt handle acidosis well, must maintain H+
what happens if we do not regulate arterial CO2 tightly ?
cause an increase in H+ ions concentration
what is the “most important equation for alveolar ventilation”
Va = CO2 / PaCO2
VT (tidal volume) x BF (breathing frequency) is the equation for what ?
Ve
CO2 / PaCO2 is the equation for what ?
Va
what are the two ways to increase ventilation :
- take more frequent breaths
- increase depth/volume of each breath
as exercise intensity increases, what happens with Va ?
Va increases with our minute ventilation
Va (alveolar ventilation) + dead space ventilation =
ventilation
if you have more CO2 does that mean you’re breathing out more or less CO2 ?
more CO2
hyperventilation = breathing more… what does this cause for CO2 ?
causes CO2 to fall
what are the three controlling exercise hyperpnea ?
- neural feed-foward
- neural feedback
- humoral feedback
which feedback is associated with “medulla and above, intrinsic oscillator” ?
neural feed-foward
which feedback is associated with muscles ?
neural feedback
which feedback is associated with chemoreceptors ?
humeral feedback
if issues with one mechanism can the others compensate ?
yes
the supra medullary inputs is associated with what ?
neural feed-toward
medullary ISK (H+) chemoreceptors is associated with what ?
humoral feedback
describe central chemo receptors :
- very responsible to changes in H+ ion concentration
- increase respiratory output with H+ ion concentration rises or pH falls
- become more acidic
mechanic /metaboreceptors afferents is associated with what ?
neural feedback
which mechanism is located with arteries / our circulatory system ?
humeral feedback
what study was an example of a case that showed that central command or those neural feedback mechanisms might not be important in driving or controlling breathing during exercise ?
the neural and humeral factors electrically induced dog experiment 1963
what study was an example of a case that showed the opposite experiment to the dog experiment (feedforward factors) ?
cat with all sensory afferent signal removed
describe the “blocking neural input from muscle in humans” experiment :
- placebo and fentanyl
- blocking inputs from muscles (potentially drive a ventilation response)
- fentanyl injection in lumbar selectively blocks all afferent signals arising from skeletal muscle
FILL IN THE BLANK :
we need Va increase in proportion to ___ in order to maintain arterial CO2, which we know is incredibly important if we allow arterial CO2 to rise…
VCO2
CO2 / PaCO2 =
Va
