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[Gofriends] Mistake in GO structure?
waku at idi.ntnu.no
Mon Jan 17 08:00:41 PST 2011
On 1/17/11 9:23 AM, Wacek Kusnierczyk wrote:
> On 1/17/11 7:12 AM, David Hill wrote:
>>> however, i must admit that the subsumption of respiratory system
>>> process by respiratory gaseous exchange is rather suspicious. for
>>> example, inhaling air into lung seems to be a respiratory system
>>> process, but calling it respiratory gaseous exchange just doesn't
>>> sound right.
>> It is at the level of the organism. We breath in to take oxygen onto
>> our bodies and we breath out to rid out bodies of carbon dioxide.
> Breathing is inhaling and exhaling air (or whatever happens to be
> around us) into the lungs. In the lungs, oxygen diffuses into the
> blood, and carbon dioxide diffuses from the blood. The circulatory
> system then takes the oxygen to other tissues, and brings a new
> portion of carbon dioxide from the tissues, while the respiratory
> system takes care of the waste and brings new oxygen for the next cycle.
> Breathing is a respiratory system process. Now,
> (a) If the whole process of removing co2 from the blood and replacing
> it with o2 is called 'respiratory gaseous exchange' (or 'respiration'
> for short, as your broad synonym acknowledges), then breathing is a
> *part* of it; saying that breathing *is* respiratory gaseous exchange
> is plainly wrong.
> (b) On the other hand, if the term 'gaseous exchange' (or 'gas
> exchange', as I find it in my textbooks) is used as it seems in
> medical terminology to name the process by which oxygen and carbon
> dioxide diffuse through alveolar cells, base membranes, and capillary
> endothelial cells in the lungs, then breathing is *separate* from
> respiratory gas exchange, and both *are* respiratory system processes
> and are *parts* of respiration.
> Either way, GO has it wrong.
Consider these two examples:
(a) When you stop breathing (e.g., while diving), gaseous exchange
continues, at least for some time.
(b) In conditions with abnormal ventilation-perfusion ratio ('wasted
blood' or 'wasted air', e.g., in inefficient inflow of blood into the
pulmonary circulation due to obstruction of a major artery or shunts, or
emphysema) gas exchange decreases while breathing increases (precisely
to accommodate for decreased gas exchange).
In these examples, equating breathing with gas exchange is obvious nonsense.
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