Why can't hemolymph in insects carry oxigen??

[Ailey]

Heya!

I was just surfing the net, trying to find the answer to this question, when I found that page and thought you might help me. I know that hemolymh serves to transport only nutrients but not oxygen... But what's the reason that it can't transport oxygen too, like in mammals?

Thanx for your help....

[Jammerz]

Hemolymph is not found in humans... you're probably thinking of hemoglobin.

The reason hemolymph doesn't have the capacity to carry oxygen is because it doesn't need to. Insects are small and their gas exchange takes place through diffusion, so they don't need an oxygen-carrying molecule to transport it.

[Ailey]

I know that it isn't found in humans... I was thinkikng about insects yes...

Thanx for your answer:) that was exactly what i needed...

[Darby]

Except that diffusion's not the right answer - insects use a separate oxygen distribution system, the tracheal system, although some do carry oxygen in the hemolymph, using a variety of carriers. Insects are too large (and waterproof) and have metabolisms that are much too high for simple diffusion to work for them.

[Jammerz]

Simple diffusion alone would not be enough to provide oxygen to larger or more active insects' tissues. Diffusion in insects is aided by the tracheal system, which delivers oxygen to all its tissues; this is aided further in some insects by simple ventilation due to movement of wings and muscle contractions. Since oxygen is provided directly to tissues through the tracheal system's aided diffusion, the hemolymph is not needed (in most insects) to carry oxygen to tissues. Insects rely far more on this type of aided diffusion than larger animals, however, that's the point I was trying to get at.
My original answer was not detailed enough.

[whizzbee]

hemolymph can't transport oxygen because it doesn't have hemoglobin. is that true?? hmmpphh...

[MrMistery]

not exactly. in some invertebrates, other respiratory pigments fulfill the role of oxygen transport. examples include hemocyanin and clorolorine.

[whizzbee]

then, hemolymph can't carry oxygen because of it doesn't contain other respiratory pigments that take role in oxygen transport?? or there's another reason for it?? what's the exact reason?

[Darby]

Sometimes hemolymph does carry oxygen - in crustaceans and marine arthropods, it's fairly common. In insects, which often have relatively high metabolisms, an open circulatory system just isn't efficient enough for oxygen distribution all by itself.

And some insects do use hemoglobin, but not contained in cells...houseflies, for example...

[February Beetle]

Bloodworms another example of insects using hemoglobin for obtaining oxygen. (aquatic fly larva that are sometimes used to feed pet fish)

[Darby]

Bloodworm is a very generic term, but I don't know of any that are insect larvae - they usually are some type of annelid, which do use oxygen carriers in their blood as the main distribution system.

[February Beetle]

http://en.wikipedia.org/wiki/Chironomidae non-biting midges are an example of an insect larvae called blood worms because of the hemoglobin.