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[Gofriends] Mistake in GO structure?

Wacek Kusnierczyk 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.

vQ



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