Control of Ventilation Flashcards
Where is the “central controller” for ventilation?
brainsteam = pons and medulla (although the cortex can override the brainstem to icnrease or decrease breathing)
The effector mechanisms on ventilation are mainly through what?
control of the respiratory muscles: diaphragm, itercostals, abdominal muscles and sternocleidomastoids
What is the most important sensor in day-to-day regulation of ventilation?
the central chemoreceptors
what do the central chemoreceptors respond to?
pH (baseically, the more CO2 that diffuses across the BBB, the more acidic the area will be - lower pH)
Where are the peripheral chemoreceptors located?
aortic arch and carotid bodies
What do the periephral chemoreceptors respond to?
pCO2, pH and pO2
WHat are the 4 lung receptors?
stretch receptors
irritant receptors
J receptors (sense fluid in the lungs)
Bronchial C fibers (trigger pain)
What type of response will the central chemoreceptors trigger when there’s icnreased H+ and lower pH?
will increase responration
What type of response will occur in alkalosis then?
hypoventilation
Why do we say the CO2 is more important for the central chemoreceptors if they’re actually sensing H+ and pH?
Because H+ can’t cross the BBB but CO2 can.
it’s the CO2 that diffuses across and then pushes the buffer reaction toward H and HCO3
What is normal CSF pH?
7.32
An aberrant CSF acidosis is eventually compensated for how?
by HCO3 retention
Which are particularly important for detecting hypoxia: aortic arch receptors or carotid bodies?
carotid bodies
Which ones: aortic or carotid - respond to a decrease in pH?
carotid
What will both carotid and aortic respond to?
hypercapcnia (but this isn’t as important as the central chemoreceptor response to hypercapnia)
What is the Herring-Breuer reflex?
the pulmonary stretch receptors will suppress further inspiration if the lungs are stretch too far
it’s relevant in yoga because it slows breathing and heart rate
What will the irritant receptors trigger in response to cigarette smoke na dother noxious gases?
bronchoconstriction and hyperpnea - to protect the lungs
What do the juxtacapillary receptors respond to? WHat’s the response?
respond to engorgement of capillaries and increased interstitial pressure - fluid in the lungs
they may mediate shallow breathing and tachypnea associated with heart failure
What will the bronchial C fibers trigger in response to noxious chemicals in bronchial circulation?
bronchoconstriction, mucous secretion and rapid shallow breathing
What do joint and muscle receptors do to respiratory rate?
movement of limbs increases respiratory rate - believed to be the stimulus for increased breathing in exercise
Response to carbon dioxide: each 1 mmHg increase in Pco2 tends to cause a _____ increase in ventilation if pO2 is help constant.
2-3 L
If CO2 is held constant, most individuals won’t respond to hypoxia until the pO2 drops below what?
50 mmHg
What are the exceptions to that?
ascent to high altitude
chronic obstructive lung disease that has adapted to changes in pH caused by CO2 retention
Again, what’s the ventilation response to acidosis?
hyperventilation
WHat happens to pCO2 and pO2 during exercise?
pCO2 decreases and pO2 increases (you breath hard don’t you?)
What causes us to breath hard during exercise?
maybe receptors in the joints and muscles
maybe increased load of CO2 to the lungs
not pH because it stays stable until very intense levels of exercise
