Lecture 4- Control of Respiration Flashcards
inspiration requires …. in motor neurons
action potentials
expiration due to … of motor neuron activity and lung …
cessation
recoil
rhythmic contraction is controlled by … neurons
pacemaker
activity of pacemaker neurons can be modulated by activity of …
pulmonary stretch receptors
The Hering–Breuer inflation reflex is a reflex triggered to prevent … of the lung. Pulmonary stretch receptors present in the smooth muscle of the airways respond to excessive stretching of the lung during large inspirations.
over-inflation
activity of pacemaker neurons can also be modulated by ….. which have inhibitory effects and can result in death
drugs (barbituates and opiates/morphine)
3 things that can affect the activity of pacemaker neurons
pulmonary stretch receptors
drugs
partial pressures of respiratory gases and [H+]
if there is a decrease in PO2 then what happens to ventilation rate
increase
if there is an increase in PCO2 or [H+] then what happens to the ventilation rate?
increase
the regulation of ventilation rate by respiratory gases and [H+] involves … in two locations
chemoreceptors
peripheral chemoreceptors (aortic and carotid bodies) are stimulated by … [H+} or … PO2
increased [H+}
decreased PO2
central chemoreceptors are stimulated by …. [H+] in extracellular fluid in brain
increased
T/F chemoreceptors can detect dissolved oxygen as well as oxygen bound to hgb
false. can only detect dissolved O2
ventilation rate increases below a PO2 of about … mmHg
60 (hgb is still 90% saturated, so vent rate responds well before blood is close to depleted)
is ventilation rate more sensitive to PO2 or PCO2?
PCO2
ventilation rate increases with a PCO2 above … mmHg
40
which is the primary regulator? central or peripheral chemoreceptors?
central
ventilation rate can be modified by non-respiratory sources of H+ such as … and …
metabolic acidosis
metabolic alkalosis
metabolic acidosis can be caused by…
excess lactic acid (exercising)
diabetes (ketones)
metabolic alkalosis can be caused by …
severe vomiting
T/F anemia and carbon monoxide poisoning do not change ventilation rate
true
why do anemia and carbon monoxide posioning not affect ventilation?
because the dissolved PO2 is the same but these conditions affect PO2 that is bound to hgb. so total PO2 is reduced but not the dissolved PO2
why is increased PCO2 from exercise not the explanation for increase in ventilation during exercise?
increased PCO2 is in the venou blood (no receptors there)
in fact PCO2 can be decreased because of hyperventilation due to ventilation matching CO2 production or better
why is decreased PO2 not the explanation for ventilation change during exercise?
decreased PO2 is in the venous blood
why is increased [H+] not the explanation for increase in ventilation during exercise?
only during strenuous exercise
what are other factors that have input to the respiratory center during exercise?
temperature
conditioned response
epi and K+
proprioceptors(joints)
what is the most likely reason for increase in ventilation during exercise?
motor cortex that sends signals to muscles is also sending signals to the resp. center
… is a deficiency of O2 at the tissue level
hypoxia
… hypoxia happens with decreased arterial PO2
hypoxic (hypoxemia)
… hypoxia is when there is normal arterial PO2 but decreased hgb O2 and decreased overall O2 content of the vlood
anemic
… hypoxia is when blood flow to the tissues is too low
ischemic
… hypoxia is when the cell are unable to utilize O2
histotoxic
example cyanide poisoning
conditions that cause hypoxemia (4)
hypoventilation
diffusion impairment
vascular shunt
vent-perf inequality
2 immediate responses to high altitude
stimulate ventilation
increased dependence on anaerobic glycolysis
what are 3 delayed responses to high altitude (acclimatization)
increased erythropoesis–> polycythemia (stim by EPO from the kidney)
increased 2,3-DPG synthesis (shift curve to right)
increased synthesis of other components of O2 delivery (capillary density, myoglobin, mitochondria)
you can train at high altitude to stimulate … production in response to low arterial PO2
EPO
old school gene doping
RBC packing or use recombinant human EPO
modern gene doping
use gene therapy to increase endogenous EPO
dangerous side effects blood doping
increased blood viscosity
increased risk of stroke
high BP
autoimmune anemia
