prac 6

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  1. why no longer hold breath at breaking point?
    • hypoxia
    • hypercapnia
    • proprioceptive influences
  2. hypoxia is when ___ and is detected by_____
    • PO2 too low
    • peripheral chemoreceptors
  3. hypercapnia is when ___ and is detected by ____
    • PCO2 too high
    • central chemoreceptors
  4. proprioceptive influences come from the _____ and makes the px ____
    • diaphragm and chest wall
    • feel uncomfy
  5. why able to extend period of holding after air expiration?
    • diaphragm was moved
    • decreased stimulation of proprioceptive receptors
  6. did hyperventilation allow prolonged breath hold and why?
    • yes
    • hypercapnia drive removed
    • increased hypoxia tolerance
  7. did starting lung vol affect breath holding time and why
    • yes
    • more vol = more O2 in lungs = can hold for longer
  8. why are we not allowed to hyperventilate with pure O2?
    • low CO2 = decr hypercapnic drive to breathe
    • high O2 = decr hypoxic drive to breathe
    • low lung volume = lung collapse
  9. how long can hold breath if hyperventilate on pure O2
  10. why do swimmers hyperventilate and why is it dangerous?
    • can hold breath longer
    • may faint underwater
  11. what happens to PCO2 and PO2 during swimming?
    • it doubles under water as increased pressure
    • goes to levels where breathing is needed
    • resurface = halves pressure = too low
  12. factors influencing breaking point
    • motivation
    • change in gas volume
  13. tensions of gases stimulate these receptors
    • medullary chemoreceptors
    • carotid and aortic bodies
Card Set:
prac 6
2014-11-04 00:22:07
prac phsl
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