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why no longer hold breath at breaking point?
- proprioceptive influences
hypoxia is when ___ and is detected by_____
- PO2 too low
- peripheral chemoreceptors
hypercapnia is when ___ and is detected by ____
- PCO2 too high
- central chemoreceptors
proprioceptive influences come from the _____ and makes the px ____
- diaphragm and chest wall
- feel uncomfy
why able to extend period of holding after air expiration?
- diaphragm was moved
- decreased stimulation of proprioceptive receptors
did hyperventilation allow prolonged breath hold and why?
- hypercapnia drive removed
- increased hypoxia tolerance
did starting lung vol affect breath holding time and why
- more vol = more O2 in lungs = can hold for longer
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
how long can hold breath if hyperventilate on pure O2
why do swimmers hyperventilate and why is it dangerous?
- can hold breath longer
- may faint underwater
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
factors influencing breaking point
- change in gas volume
tensions of gases stimulate these receptors
- medullary chemoreceptors
- carotid and aortic bodies