Path followed:
1. Is the fault in the components that perform any physical action?
Answer: No
2. Is the faulty component part of the mechanism’s body?
Answer: Yes
3. Is the faulty component in the structure of the mechanism?
Answer: Yes
4. Does the fault appear in components that provide rigidity to the mechanism?
Answer: No
5. Is the faulty component responsible for supporting other components?
Answer: No
6. Does the faulty component provide filtration?
Answer: No
56) Japanese sea lily, Metacrinus rotundus
Japanese sea lilies can be found off the west coast of Japan (Hunter). The crown of the sea lily is comprised of arms and pinnules that are used to acquire food. Sea lilies have the capacity to regenerate their crown if it was to get amputated or damaged.
After the crown of the sea lily is amputated a small depression is left on the top of the plate which is quickly covered by a blastema (Amemiya
& Oji)). The blastema is made of mesenchyme cells that came from unspecialized amoebocytes. Amoebocytes came from the brachial nerve and give rise to the stumps that the arms will grow out of. The stumps regenerate the arms and pinnules from mesenchyme cells that differentiated into chondrocytes (Amemiya & Oji). The chondrocytes proliferate and form the cartilage of the arms and pinnules. Mesenchyme cells also proliferate and differentiate into coelomocytes that form the coelomic system in the arms and pinnules of the sea lily. The coelomic canals are able to continue to proliferate and provide enough cells to regenerate the entire coelomic system in the sea lily crown (Kondo & Akasaka). Nerve cells also differentiate into the neurosecretory-like cells and axonal processes which help relay siganls. Finally myocytes surround the nerves and differentiate into the different muscular tissues. Once the arms and pinnules are fully formed the blastema is disintegrated and the cells stop proliferating to differentiate.
Hunter, Aaron. “Metacrinus Rotundus (Japanese Sea Lily).” Metacrinus Rotundus (Japanese Sea Lily). Natural History Museum, 2014. Web. 7 Dec. 2014.
http://www.nhm.ac.uk/nature-online/species-of-the-day/evolution/metacrinus-rotundus/
Amemiya, Shonan, and Tatsuo Oji. “Regeneration in Sea Lilies.” Nature 357.6379 (1992): 546-47. ProQuest. Web. 7 Dec. 2014.
http://0-search.proquest.com.library.uark.edu/docview/204446446?accountid=8361
Kondo, M., and K. Akasaka. “Regeneration in Crinoids.” Development, Growth, and Differentiation 52.1 (2010): 57-68. NCBI. Web. 7 Dec. 2014.
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