Re: The heart of a Brachiosaurus

[brandonc@advant.com (Haist, Brandon)]

I have read many explanations of Sauropod Hearts.  Some say that they were
slighly differently shaped so as to make a stronger heart pump, stroke
volume, and blood pressure.  I would think that this would lead to what you
suggested, strokes.  I still feel that considering that Sauropods where
novel in thier design and size that at least some of their anatomy was
different from anything we have today.

As for giraffes, I read that the animals have unique adaptations to their
anatomy; they have valves in the neck arteries.  According to my Human
Anatomy & Physiology class, normally only lymph vessels and blood veins have
valves; arteries do not due to already high pressure.  Since giraffes are
tall in the neck, they keep the blood from stalling or falling backwards by
blocking the only direction in which they travel.

Recently there was that little dino in Italy preserved with its organ,
several specimens have been found through the years with skin, anatomy,
muscles, even food preserved along with bones.  I believe that someday in
the future a Sauropod dino skeleton will be found containing enough of its
soft anatomy that we will be able to better answer this question.
~Brandon Haist




-----Original Message-----
From: John Bois <jbois@umd5.umd.edu>
To: GGreyOwl@aol.com <GGreyOwl@aol.com>
Cc: dinosaur@usc.edu <dinosaur@usc.edu>
Date: Wednesday, November 25, 1998 2:28 PM
Subject: Re: The heart of a Brachiosaurus


>
>I don't know the answer to your question.  But here are some things to
>think about.  Much depends upon whether or not the animal raised its head
>directly above its body, or whether it browsed closer to the ground.  In
>the first case one would expect high blood pressure or some fantastic
>adaptation (eg., 7 neck hearts) to get the blood all the way up.  I
>believe brain tissues (for example) in all creatures are equally prone to
>bursting (as in strokes).  Therefore, if excessive pressure was needed to
>pump blood up then one would expect an excessively high rate of strokes.
>We have no way of knowing whether or not this occurred.  I wonder if
>giraffes experience more of these difficulties?
>
>Either way, moving blood around a huge body was just one of the
>physiological problems to be solved by these gigantic creatures.  Indeed,
>one could argue, as I have, that being big was a rather pathological
>condition.