2. General Members of Phylum Arthropoda In the Subphylum Crustacea Found in freshwater steams and ponds worldwide Coelomates Triploblastic Bilateral symmetry Protostomes Complete digestive systemhttp://islandwood.org/kids/stream_health/Images/Crayfis Joined appendages h%20photo.jpg Exoskeleton made of chitin 3. Crayfish Digestive System 1st- breaks apart food items 2nd- particles continue from these mouthparts to theinternal system where nutrients are absorbed 3rd- true digestion takes place Finally, waste is expelledhttp://mackers.com/crayfish/internal.jpg 4. Necessary SystemWithout this digestive system, crayfish would not be ableto: break up food particles secrete enzymes absorb nutrients store glycogen and fat http://2.bp.blogspot.c om/- produce yolk proteins for developing eggs 0GqhqXD3BuU/T- wgMxX6OSI/AAAAA AAABsY/_irnr4I1fl0/s 1600/crayfish-with- minnow-large.jpg store calcium prior to molting 5. Anatomical Features Foregut-lined with cuticle that is continuous with exoskeleton-enlarged stomach = chambers for storage, grinding and sorting-finely grinds up particles, sending smaller ones to next region(midgut) & sending back larger particles for more grinding Midgut-intestine-length varies with body shape and size, diet -has mucous membranes that encase the remaining particlesinto pellets & forcefully pushing into the hindgut 6. Anatomical Features (Cont.) Hindgut -short, to anus -dispose of the digested and undigested particles not absorbed by thecrayfish Green gland -right behind the brain of the crayfish -gland that helps filter fluid waste from blood-not entirely associated with the digestive system, but effectsnutrients and filtration of nutrients from the foods that the animal ingests Digestive gland-secretes digestive enzymes and aids in the absorption of theproducts of digestion 7. Its Job crayfish chews food..particles pass through theesophagus..food then enters the cardiac stomach..with thehelp of enzymes,cardiac stomach further breaks up theparticles..food particles enter pyloric stomach which finelygrinds up the particles,sending the smaller ones tomidgut..sends back larger particles for more grinding..particles small enough to exit the pyloric stomach enter themidgut.. dorsal abdominal artery removes nutrients throughblood vessels and into bodily fluids..midguts mucousmembranes cover remaining particles into pellets..midgutforcefully pushes into the hindgut..hindgut dispose of thedigested and undigested particles not absorbed by thecrayfish.. contractions complete the food items digestion..wastes excreted through the anus 8. http://magickcanoe.com/crayfish/crayfish-w-eggs-large.jpg http://www.biologyjunction.com/images/Crayfish42D.jpghttp://www.caaquaculture.org/wp-content/uploads/2012/06/signal- http://crescentok.com/staff/jaskew/isr/biology/cfish5.gifcrayfish.jpg 9. Biography Farkas, Andrea Lynn. "What Happens to the Digested Food in a Crayfish?" EHow. Demand Media, 27 May 2011. Web. 11 Apr. 2013. "Biology 102; Animal Biology." Biology 102; Animal Biology. N.p., n.d. Web. 11 Apr. 2013. "Marine Bio." : Crayfish- Virtual Dissection. N.p., n.d. Web. 11 Apr. 2013. "Two Pairs of Maxillae Serve as Accessory Mouthparts." Subphylum Crustacea. N.p., n.d. Web. 11 Apr. 2013.
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