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Re: Necks and Brains
On Mon, 1 Apr 1996, Lloyd Gabel wrote:
> The diving reflex in aquatic mammals is a good example of selective
> blood flow redistribution and shunting to the nervous system during hypoxic
> periods by vasoconstriction and dilation. We humans reflexly shunt blood
> towards the brain when we suddenly stand up from a sitting or prone position
We humans also reflexively shunt blood towards the brain when the face
becomes covered with water, like diving mammals; but that is another story...
> James Norton's comments on tracheal dead space and airway resistance in long
> necks are well taken,
IMHO, it must be borne in mind in this sort of discussion that sauropod
lungs were likely set up more like those of birds than of mammals or
lizards, with the air entering a system of air sacs as it is inhaled and
*exiting* through the lungs. I'm not sure personally just what effects,
if any, this might have on the air dynamics in a sauropod's windpipe,
but it is something to consider.
Does air enter and exit a bird's respiratory tract through the same opening?
> Lloyd Gabel LPGABEL@MSN.COM
Pacific Lutheran University
Tacoma, WA 98447