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From: lonetto@phri.UUCP (Michael Lonetto)
Newsgroups: net.bio,net.sci
Subject: Re: Do ants have hearts?
Message-ID: <271@phri.UUCP>
Date: Mon, 17-Jun-85 21:33:33 EDT
Article-I.D.: phri.271
Posted: Mon Jun 17 21:33:33 1985
Date-Received: Wed, 19-Jun-85 02:11:20 EDT
References: <663@cadovax.UUCP>
Organization: Public Health Research Inst. (NY, NY)
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Xref: watmath net.bio:220 net.sci:351

> 
> Here is a question for the entomologists and the invertebrate zoologists:
> 
>      How is food and oxygen circulated in invertebrates?
                                            ^^^^^^^^^^^^^

The question is a little broad as phrased.  Since the subjuct line mentioned
ants:

Insects have an "open" circulation system consisting of "hemolymph",
(which serves the purposes of blood) which is circulated by a simple
heart and dorsal artery.  The artery leads to the ends of the organism
where the "blood" flows into the body cavity and, eventually, back to
the heart(which has a direct input).  Oxygen exchange is accomplished by
a system of trachea which branch throughout the body and are connected
to the outside air by spiracles, which are small openings in the
exoskeleton.  Since oxygen and CO2 don't have to diffuse far from the
trachea a fairly simple circulatory system is quite efficient.  

Incidentally, this is one of the factors limiting the size of insects.
Aren't you glad?

Michael Lonetto   PHRI

allegra!phri!lonetto
-- 
Michael Lonetto  PHRI  NYC  (allegra!phri!lonetto)

"Some win, Some lose, Some refuse to play"