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: Yes
5. Can the faulty component be removed from the mechanism?
Answer: No
6. Is the fault in load bearing components?
Answer: Yes
7. Do multiple versions of the components exist for the faulty component?
Answer: No
8. Can the mechanism continue to function until the component is replaced?
Answer: No
9. Do debris need to be cleared from the damaged area?
Answer: Yes
66) American bullfrog, Rana catesbeiana
American bullfrogs can be found in Canada, Mexico, and the United States (Santos-Barrera et al.). These frogs are freshwater dwellers and lay their eggs in sacs in the water to develop. The American bullfrog tadpoles have the ability of regenerating their tail after it has been amputated in some way.
Shortly after the tail has been amputated epithelial cells migrate towards the wound. These cells proliferate and join together to form the new epithelium that covers the wound. Under the epithelium a blastema is formed from blastemal cells (Atkinson et al.). These cells are undifferentiated and proliferate to aid in the regeneration process. Macrophages swarm to the wound as well and clear the wound of any debris such as dead cells or infection. The blastema cells form the notochordal outgrowth and nerve axons in the newly regenerating tail (Atkinson et al.). Myoblasts are also found in the blastema where they fuse together and form the myotubules (Atkinson et al.). These myotubules develop into the musculature of the tail such as the muscle fibers and tendons. The epithelial cells also help to form capillaries that supply blood to the tail. Once the tail has reached its maximum size the blastema will disintegrate and the cells will stop proliferating and differentiating.
Santos-Barrera, G., Hammerson, G., Hedges, B., Joglar, R., Inchaustegui, S., Lue Kuangyang, Chou Wenhao, Gu Huiqing, Shi Haitao, Diesmos, A., Iskandar, D., van Dijk, P.P., Masafumi Matsui, Schmidt, B., Miaud, C. & Martnez-Solano, I. 2009. Lithobates catesbeianus. The IUCN Red List of Threatened Species. Version 2014.3. Web. 9 Dec. 2014.
http://www.iucnredlist.org/details/58565/0
Atkinson, Kristine H., Burr G. Atkinson, and Peter A. Merrifield. “Morphogenetic Sequences during Tadpole Tail Regeneration.” Canadian Journal of Zoology 54.8 (1976): 1314-325. NRC Research Press. Web. 9 Dec. 2014.
http://www.nrcresearchpress.com/doi/abs/10.1139/z76-149?journalCode=cjz#.VK83uWTUu8k
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