Friday, February 5, 2010

What are the advantages/disadvantages of the cuticle covering of the nematodes?

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Nemotodes, like other aschelminthes, are covered by a nonliving, acellular protective covering called a cuticle. The cuticle of nematodes is a complex four-layered structure. The main component is inelastic collagen which gives the cuticle the properties of impermeability and rigid strength. For movement to occur, however, the cuticle must be elastic, and the collagen is laid down as a spiral latticework of parallelograms with protein in between. Movement of the cuticle results ln a change in the angle between the fibers of the lattice. Peel a piece of cuticle from your dissected Ascaris. Make a wet mount and examine it under the microscope. Can you see the plates and layers? Since cuticles form relatively rigid exoskeleton, they must be periodically shed (molted) to allow for growth.


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