(But...) Re: Lung Capacity

["Charles Roustan" <charlesroustan@softhome.net>]

Umm... I thought I had sent this before.... sorry if you are receiving it
twice.

Sorry for the delay and thank you for the replies. A reference was mentioned
to me (I haven't read it, though) by Dr. Richard Hengst (I think he's an
anatomist? anyway, I have seen his name in the archives of this list) from
Purdue University, apparently he measured the ribs in the Apatosaurus at the
Field Museum and calculated its lung volume because the ribs around the
lungs are of different shape than the ribs in the abdominal region. Then he
went on to conclude that the maximum volume change while breathing was
limited by the rotation of the ribs back and forth, not bellying out and
based on this value he calculated the maximum volume change that actually
took place when the animal breathing and he said that it was about 1/40 of
total lung volume, I take that to mean that the whole air in the lungs got
exchanged 100% each 40 breaths (or am I wrong?).

In contrast, he seems to have said (I repeat, I have NOT read this paper)
that in birds the sternum and the ventral ribs belly out during flight and
the total air in the lungs gets exchanged in only 7 breaths or so. I don't
know about mammal ribs.

Also, is the presence of a diaphragm important -in those groups that have
it-? apparently Hengst did not mention anything about the
complexity/simplicity of the lungs, but according to what you say it's of
great importance, right? but then again, I haven't read the thing, so maybe
he DID take it into account.

I was planning to look up all of this for using it in a homework paper but I
would like to hear your opinions. Should I bother finding the paper or
should I move in another direction? due to my geographical location it's a
bit hard for me to find papers.

Thanks again,

Charles