Re: Holloway/Morgan
Phil Nicholls (pnich@globalone.net)
Sun, 23 Jul 1995 00:02:39 GMT
Ralph L Holloway <rlh2@columbia.edu> wrote:
>On Thu, 20 Jul 1995, Elaine Morgan wrote:
>> Whether we were right or wrong, I doubt if anyone would have dreamed of
>> doing research in the 8o's and 90's into the eccrine glands of
>> anthropoids if it hadn't been for us.
>I am not sure about this. Perhaps you are right. But during the '60's
>and 70's there was atremendous burst of interest in primates, both as
>miniture us's and as phenomena worthy of study in their own right. When I
>reread Montagna and Ellis 1963 I thought where have been all the newer
>quantitative histological studies of this proble.? Where would Montagna
>take us today? My point is I'm not at all sure that it was the AAH'ers
>who have been the primary movers of such research. I would be more
>willing to see the research as a natural development of the braod range
>of interest in primates and human evolution.
> Has there really been that much research into eccrine/apocrine glands
>in the '80's and '90's?. I am not aware of very much, so bring me up to
>date.
There has been some. I have posted references to more recent studies.
To summarize this
1. No species of primates so far studied used apocrine glands in
thermoregulation.
2. Small bodied primates are nocturnal and do not require
more complex thermoregulation.
3. Medium size diurnal primates such as lemurs and sifiakas pant
rather than sweat.
4. Large bodied primates, when subjected to heat stress, produce
eccrine sweat though not in amounts that would provide
significant cooling.
Large bodies primates for the most part are not subjected to intense
heat stress. Those that are have adapted via behavior. They are
inactive during the hottest parts of the day and rest in the shade.
It is likely that the thing that tipped the balance in humans was the
enlargement of the brain. There are differences in the way eccrine
glands are innervated by cholinergic neurons of the sympathetic
nervous system. This is unual since the sympathetic nervous system is
mostl noradrenergic. The differences in the two types of
neurotransmitters is significant. Noradrenaline is associated with
"quick and dirty" responses. Apocrine glands are Noradrenergic.
Horses sweat profusely after running, releasing a lot of apocrine
sweat. It is a "mass action, whole body" response the sympathetic
nervous system. Acetylcholine, associated with cholinergic neurons,
is associated with more the more controlled, discrete responses of the
parasympathetic nervous system.
Hence the neurological controls over eccrine sweat allow better
regulation (control) of the sweating process. The mechanisms is
present in apes and monkeys but is evoked only in response to extreme
heat stress. Hominids modified this existing system when the
enlargement of the brain required better thermoregulation. Under
this scenerio, Australopithecines would have been more like gorillas
and champanzees in terms of sweating.
Phil Nicholls (pnich@globalone.net)
"To ask a question you must first know most of the answer."
- Robert Sheckley
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