Path followed:
- Is the fault in the components that perform any physical action?
Answer: Yes
- Is the fault in components that move?
Answer: Yes
- Is the fault in components that make the mechanism move?
Answer: Yes
- Is the faulty component designed to move the mechanism around?
Answer: Yes
- Is the faulty component needed for stability?
Answer: No
- Does the faulty component manipulate smaller objects?
Answer: Yes
- Is the faulty component rigid?
Answer: Yes
- Are there any external resources that can be used by the mechanism?
Answer: No
11) Hairy Frog, Trichobatrachus robustus
Hairy frogs are found in the Central African country Cameroon. They can be found in rainforests and their tadpoles are found in freshwater (“Trichobatrachus Robustus”). Hairy frogs have the ability to break their bone through the skin to produce a claw on their back foot and then heal itself.
When not threatened, the frogs bone lies within the flesh connected to a small, bony nodule by collagen. There is also a muscle that resides under the bone and connects to the lower half of the ‘claw’ (Young). When the frog is threatened it contracts the muscle, which breaks the collagen bond formed between the nodule and bone. This in turn allows the bone to be pulled down and puncture through the connective tissue and skin to form the ‘claw’ (Young). It is not knowing how the ‘claw’ is retracted back into the skin but researchers believe it is done passively as the muscle relaxes (Young). Once the claw is back in the skin, the collagen bond presumably reforms by fibroblasts invading the region and producing the protein, vimentin, which is a marker for mesodermal cells that helps to produce muscle. They also transform to produce epithelia to help in tissue repair. The skin also heals very quickly due to the fact that it is an amphibian. Frogs are known to have peptides called magainins that are antifungal, antiparasitic, antibiotic, and antiviral, which helps the wound from getting infected and slowing the healing process (“A World Without Amphibians”). Frogs heal quickly by being able to switch on angiogenesis, which stimulates blood vessel growth (Queen’s University, Belfast). They are also able to heal their skin quickly through regeneration. The wound undergoes immediate hemostasis to stop the blood loss. Wounds are closed by epidermal cells migrating to the site, joining together through tight junctions, and forming two or three layers (Kawasumi et al.). Dedifferentiation causes mononuclear cells to infiltrate the site and produce mesenchymal cells to repair the wound. Re-differentiation occurs and produces the skin and exocrine glands.
“Trichobatrachus Robustus.” Eol. Encyclopedia of Life, 2011. Web. 20 Nov. 2014.
http://eol.org/pages/331425/details
“A World Without Amphibians.” Frogs: The Thin Green Line. PBS, 28 Mar. 2009. Web. 20 Nov. 2014.
http://www.pbs.org/wnet/nature/frogs-the-thin-green-line-a-world-without-amphibians/4852/
Yong, Ed. “‘Wolverine’ Frogs Pop Retractable Claws from Their Toes.” Web log post.‘Wolverine’ Frogs Pop Retractable Claws from Their Toes. Science Blogs, 27 May 2008. Web. 20 Nov. 2014.
Queen’s University, Belfast. “Scientists unlock potential of frog skin to treat cancer.” ScienceDaily. ScienceDaily, 7 June 2011. Web. 20 Nov. 2014.
http://www.sciencedaily.com/releases/2011/06/110606181137.htm
Kawasumi, Aiko, Natsume Sagawa, Shinichi Hayashi, Hitoshi Yokoyama, and Koji Tamura. “Wound Healing in Mammals and Amphibians: Toward Limb Regeneration in Mammals.” Current Topics in Microbiology and Immunology 367 (2012): 33-49. Springer-Verlag Berlin Heidelberg. Web. 20 Nov. 2014.