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: Yes
5. Is the fault only limited to non-sensory components?
Answer: Yes
6. Does the adaptation need to occur before deployment?
Answer: No
7. Can the replaced component be removed?
Answer: Yes
70) Mexican Axolotl, Ambystoma mexicanum
The Mexican Axolotl is a salamander in the amphibian class. It can live 10 to 15 years in the wild but are considered endangered due to the water pollution, trading business, and being a food delicacy in Mexico (ÒMexican AxolotlsÓ). Axolotls have the unique ability of regenerating their spinal cord if it was to ever get damaged.
One of the major differences between urodeles and mammals is the microenvironment that the cells are housed in. The axolotl has many radial glial cells that are able to dedifferentiate, proliferate, and re-differentiate in a mesenchymal blastema that forms over the wound site (Gilbert). After the spinal cord is injured ependymal cells proliferate and interact with the extracellular matrix (ECM) to form the cranial and caudal ependymal outgrowths that connect to form the spinal cord (Chernoff). Macrophages also migrate to the wound and remove the dead neurons and neural cells. The axons are formed by the guidance of polysialyated-neural cell adhesion molecules (PS-N-CAM) controlling the re-differentiation of ependymal cells (Chernoff). Next the fibrous material surrounding the spinal cord creates muscles and tissues that differentiated from fibrous astrocytes (–). Once the axons, spinal cord, and surrounding muscles are formed the blastema will disintegrate and the cells will stop proliferating.
“Mexican Axolotls.” National Geographic. National Geographic, n.d. Web. 9 Dec. 2014.
http://animals.nationalgeographic.com/animals/amphibians/axolotl/
Gilbert, Scott F. “Regeneration.” Regeneration. U.S. National Library of Medicine, 18 Dec. 2000. Web. 9 Dec. 2014.
http://www.ncbi.nlm.nih.gov/books/NBK9971/
Chernoff, Ellen A.G. “Spinal Cord Regeneration: A Phenomenon Unique to Urodeles?” International Journal of Developmental Biology 40 (1996): 823-31. IJDB. Web. 9 Dec. 2014.
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