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: No
4. Does the faulty component responsible for visual data acquisition?
Answer: No
5. Is the faulty component used for sensing the location of objects?
Answer: Yes
6. Is the faulty component rigid?
Answer: Yes
7. Is the faulty component used for protection?
Answer: Yes
114) Porcupine, Erethizon dorsatum
Porcupines can be found in Canada and the United States (ÒPorcupineÓ). They are known for throwing their sharp quills at predators to have a chance at escaping. Porcupines have the ability of regenerating their quills if they were to get torn off or thrown off in defense.
Soon after the quill has been lost or used in self-defense another quill begins to regenerate to take its place. The quill is made an outer sheath and a porous core (Yang et al.). To form the quill there are specialized epidermal cells in the epidermis of the porcupine (Yang et al.). Once the quill is lost the epidermal cells begin to proliferate to generate enough cells that will remake the quill. The epidermal cells will then differentiate into the cells that will create the outer sheath of the quill. Other cells will differentiate into the cells that create the porous foam in the middle of the quill (Taggart & Starr). As the quill gets longer more cells differentiate into the foam. Once the quill has reached its maximum size the epidermal cells will stop proliferating and differentiating until another quill is lost.
“Porcupine.” National Geographic. National Geographic Society, 2015. Web. 3 Jan. 2015.
http://animals.nationalgeographic.com/animals/mammals/porcupine/
Yang, W., C. Chao, and J. McKittrick. “Axial Compression of a Hollow Cylinder Filled with Foam: A Study of Porcupine Quills.” Acta Biomaterialia 9 (2013): 5297-304. Elsevier. Web. 3 Jan. 2015.
Taggart, Ralph. “Principles of Anatomy and Physiology.” Biology: The Unity and Diversity of Life. By Cecie Starr. 11th ed. Belmont: Thomas Learning, 2006. 483. Print.
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