2006-06-26 05:38:51 · 4 answers · asked by star 1 in Science & Mathematics ➔ Biology
Crab's heart...
A crab's heart is located dorsally in the center of the carapace and is suspended under the surface of the carapace by strands of connective tissue. It is single-chambered.
Worm heart...
Earthworms possess five hearts. The calciferous glands between the hearts manage excess calcium in the worm's diet, a problem you may have if you eat a lot of dirt.
2006-06-26 05:53:17 · answer #1 · answered by Anonymous · 0⤊ 0⤋
What type of worm are you talking about? Annelids (aka: earthworms) exhibit a closed circulatory system and do not have a proper heart, but rather a modified aorta that has 5 branches which serve the same purpose. (More primitive worms like flatworms do not possess a true circulatory system, however.) Crabs are arthropods and thus posses what is called an 'open circulatory system.' Animals that bear an open circulatory system do not have specific blood vessels like those of vertebrates, but rather have what is called "hemolymph" (which is analogous to blood in that it contains an oxygen-binding molecule, but also is comprised of interstitial fluid) housed within a hemocoel (large body chamber). Instead of the heart pumping the hemolymph to the tissue via a blood vessel network as it would in a more evolved, closed circulator system, the hemolymph is pushed around the hemocoel by contractions of the heart. When the heart relaxes, the hemolymph is drawn towards it, away from the systemic tissues and vice versa.
2006-06-26 17:16:15 · answer #2 · answered by Girl Biologist 2 · 0⤊ 0⤋
The Worm (my brother-in-law has a very small heart. The Crab (my sister) has no heart at all.
Keep smiling!!!
2006-06-26 12:48:08 · answer #3 · answered by mykidsRmylife 4 · 0⤊ 0⤋
they both pump blood
2006-06-26 12:45:46 · answer #4 · answered by Anonymous · 0⤊ 0⤋