Path followed:
1. Is the fault in the components that perform any physical action?
Answer: Yes
2. Is the fault in components that move?
Answer: No
3. Is the fault in the mechanisms controls?
Answer: Yes
4. Is the fault in the components responsible for sending signals?
Answer: No
5. Does the faulty component control any other functions in the mechanism?
Answer: No
6. Does the fault effect all components responsible for transmitting sensory data?
Answer: No
3) Sea Cucumbers, Holothuria glaberrima
Sea Cucumbers can be seen all over the globe in oceans, preferably on the floor of deep oceans. They can live 5 to 10 years in the wild and can range from 0.75 in to 6.5 ft (ÒSea CucumbersÓ). They are known for being able to regenerate their radial nerve cord.
Radial nerve chords are made of etoneural (EN) and hyponeural (HN) bands separated by connective tissue (CT). If the Sea Cucumber was to injure its radial nerve cord (RNC) it would under axonal growth and then remodel itself to its original morphology. When the RNC is injured it would immediately cause fan-shaped stumps, which are caused by swelling of the EN band (Miguel-Ruiz et al.). Morulas are found to surge
into the proximal end of the nerve stumps where they interact with RNC cell bodies and regrowing fibers. Spherulocytes are also found proximal to the nerve stump but decrease as the nerves are regenerated. RN1-labeled fiber bundles could be seen protruding from the stump toward the other stump along the substratum wall (Miguel-Ruiz et al.). In order for the fiber bundles to grow, the cells in between the stumps and in the fiber bundles underwent extreme cell division. The fiber bundles eventually grew enough to connect the two ends and make the RNC. Frayed fibers are believed to be peripheral nerves that could go into the EN and HN bands (Miguel-Ruis et al.). As more time passed the CT band could clearly be seen differentiated between the EN and HN bands from the surrounding tissues regenerating themselves through cell proliferation as well.
“Sea Cucumbers.” National Geographic. National Geographic Society, 2015. Web. 2 Nov. 2014.
http://animals.nationalgeographic.com/animals/invertebrates/sea-cucumber/
Miguel-Ruiz, Jose E San, Angel R. Maldonado-Soto, and Jos E. Garca-Arrars. “Regeneration of the Radial Nerve Cord in the Sea Cucumber Holothuria Glaberrima.” BMC Developmental Biology. BioMed Central Ltd, 6 Jan. 2009. Web. 2 Nov. 2014.
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