Spiders

[poochpamperer]

I have a question about arthropods.
In the Phylum Arthropoda, the phylum characteristic is a dorsally located heart, and an open circulatory system. Meaning that if you flip a crab upside down, he won't be able to wash the blood over his organs, so he will die.
Now, in the class archacnidad, with the spiders (who also have dorsally located heart and an open circulatory system) ~~How can they stay upside down on the ceiling for hours without dieing for lack of ablitity to wash the blood over his organs?

[Darwin420]

"I have a question about arthropods.
In the Phylum Arthropoda, the phylum characteristic is a dorsally located heart, and an open circulatory system. Meaning that if you flip a crab upside down, he won't be able to wash the blood over his organs, so he will die.
Now, in the class archacnidad, with the spiders (who also have dorsally located heart and an open circulatory system) ~~How can they stay upside down on the ceiling for hours without dieing for lack of ablitity to wash the blood over his organs?"


From my understanding with spiders is that they have arteries with high pressure that push the blood onto the tissue cells of the spider. The pressure is so high that even while be upside down, there is enough pressure for the blood to be pushed into the tissue cells.

This is just my guess, could be wrong.

[MichaelXY]

Try looking here
http://books.google.com/books?id=XUgyqx ... n#PPA53,M1

[Darby]

The crab thing doesn't really make sense, either - the whole point of an open circulatory system is that it's not really critical - a crab on its back for hours and hours might be affected, but it doesn't even seem like that should be true.

[Cat]

Darwin420 is right, and I believe so is Darby (leaving out the part about "circulatory system is that it's not really critical"). After reading your claim " if you flip a crab upside down, he won't be able to wash the blood over his organs, so he will die", I tried to find about it since I never heard about such a thing before! I cannot find any scientific or even non-scientific reference for the "death by inversion". Where did you get this idea?

[poochpamperer]

I just heard my Biology Professor talk about it...
She said that when you flip a crab, it will die because of all the blood pooling on it's back,
so it isn't able to "wash it" over it's organs...

Thanks Michael for the link