Most of the living cells in cnidarians are in direct contact with water causing them to live in clean, constantly moving water and they therefore do not have or need true a circulatory system. Respiration in cnidarians occurs without any of the following specialized organs such as trachae, gills or lungs. To respire, the cnidarian obtains oxygen from water and it diffuses directly through the tissues of the cnidarian. Gaseous wastes are also eliminated by diffusion but solid wastes are discharged through the mouth opening as cnidarians do not have anuses. The gastrovascular cavity functions as a transport system for the animal. The cavity circulates fluid through the organism by squeezing the body wall which pushes water in and out of the body.
Saturday, February 17, 2007
RESPIRATION AND CIRCULATION
Most of the living cells in cnidarians are in direct contact with water causing them to live in clean, constantly moving water and they therefore do not have or need true a circulatory system. Respiration in cnidarians occurs without any of the following specialized organs such as trachae, gills or lungs. To respire, the cnidarian obtains oxygen from water and it diffuses directly through the tissues of the cnidarian. Gaseous wastes are also eliminated by diffusion but solid wastes are discharged through the mouth opening as cnidarians do not have anuses. The gastrovascular cavity functions as a transport system for the animal. The cavity circulates fluid through the organism by squeezing the body wall which pushes water in and out of the body.
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4 comments:
You're a fag
I DON'T GET IT ....HOW CAN CNIDARIANS HAVE A TRACHEAE IF THEY ARE NOT TERRESTRIAL?
They don't have tracheae as thyt are aquatic
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