Analysis Literature about Human Appendix - Essay Example

Human Appendix: Critical Review of Literature Introduction Human vermiform appendix is morphologically the undeveloped distal end of the cecum. This organ is considered vestigial in humans without any physiological role as such until recently. Therefore, appendix being considered a mechanical or structural entity only, removal of of this organ in case of inflammatory pathologies has been established to be the widely accepted treatment. Appendicitis is still considered to be one of the most common serious emergencies occurring in human body. Although attached as an appendage to cecum. The appendix has hardly any lumen in health. Its covering by peritoneum and attached mesoappendix can be explained from its embryologic origin from the cecum. The seemingly innocuous lumen which can barely admit a match stick leads to the presupposition that it has no function, which was originally supported by its small arterial supply. The microscopic picture of the appendix in the luminal aspect, however, is marked by presence of inner lining of colonic-type mucosa that covers the lymphoid tissue located within its wall which is supplied by small lymphoid vessel. Until the advent of current research and findings thereof, the surgeon were happy to contend that removal of appendix does not confer any adverse effects, more so on the face of life-threatening nature of the disease of acute appendicitis. However, discovery of the fact that K cells within the mucosal crypts and the lymphoid tissue may serve more functions that are thought. In fact some authors went ahead to term the collections of the lymphoid follicles within the appendix to be abdominal tonsils, disruption of the blood supply to which and removal of which may have a bearing on the infection in the abdominal cavity. In this assignment, a critical review of the Bollinger et al. (2007) paper titled " Biofilms in the large bowel suggest an apparent function of the human vermiform appendix" will be presented which tends to counter the concept that human vermiform appendix is a vestigial, inert organ with no physiological activity. 2. Host-mediated biofilm formation by colonizing bacteria It is now an established concept that human large intestine is colonized by bacteria which belong to both harmful and helpful categories, and the character of this biofilm is determined by the immune interactions between the mucosa and the bacteria. Other studies have shown that the activity of the mucosa is manifested through formation of biofilms. The authors present evidence from different other life forms such as plants and corals and are successful in establishing their concepts. 3. Host-mediated biofilm formation in the mammalian gut The formation of biofilms by commensal bacteria happens at areas of mucous membranes due to the fact that mucus secreted from the inner lining act as probiotic agents for these bacteria. An active mucosa will have to secrete materials which will help the commensal bacteria to grow and form a biofilm and this is based on a symbiotic relationship that the biofilm on a mucosal surface will provide protection to the colonized area against potential harm caused by pathogenic bacteria. Thus it can be concluded that biofilm formation by colonizing bacteria is a host mediated process. The review of literature presented in this section is extensive and exhaustive. When the reader goes through this section, he has no problem in understanding the current evidence as to how biofilms are important in maintaining the integrity of colonic mucosa. Through this the reader can also contemplate easily the rationality of the concept that if biofilms are encountered in the vermiform appendix, being developmentally a part of the colon, the appendicular mucosa will also be reactive. This logical correlation had then been supported by the authors by findings from literature that this activity pertains to mucosa immunity related to IgA. Thus this established the concept that biofilms also has role in exclusion of pathogenic bacteria form the film, a breach of which will precipitate an infection. As the reader goes on, there is no difficulty for the reader to assess proof from human appendix samples both in health and disease and the photomicrographs attached. 4. The appendix as a ''safe house'' for beneficial bacteria In this section the authors propose a function of the appendix which could be that of a compartment which stores commensal microflora for release into the contaminated environment of the colon in cases of eventuality. The structural innocuousness of appendicular lumen and its location may work toward protecting these appendicular films from the contaminated fecal stream of bacteria. This concept was depicted through a schematic diagram which has been explained well, which is followed by evidence from literature which has been presented according to the gradation of the evidence. At the end of this the reader can rationally correlate biofilm preservation in healthy appendix and secretory IgA activity at the mucosal milieu, which can further be substantiated by the presence of rich submucosal lymphoid tissue. The authors keep no doubts unturned by arguing against this concept, and the reader definitely believes that appendicular mucosal immunity indeed plays important roles in maintenance of the commensal flora. 5. The human appendix: useless in the face of modern medicine and sanitation practices' In this section the authors use the baseline literature review to open the debate as to whether removal of appendix is justified. The authors argue strongly that with modern medical care and sanitation procedures, there may actually be no necessity to maintain commensal flora as an appendicular storage. Rather than risking the life with a possible appendicitis, it would then be better to remove it. As indicated in the introduction of this assignment, the functional nature of this organ and the specific function that it subserves may be difficult to prove due to lack of an animal model but there is strong evidence that it has some functions. In this section, the authors provide more evidence from literature that modern medicine and high sanitation level may open another pathway of immune reactivity within the appendix which may lead to the intense inflammatory process within appendix. This can be indirectly supported by the fact of high incidence of acute appendicitis in the developed western world. Conclusion Although this study fails to reach a conclusion about the functional nature of appendix as an organ as opposed to the prevalent concept that it is just a vestigial organ, this study consolidated the evidence from literature and placed the rational argument that it is time to investigate the nature of function of this organ. While theoretical concepts have been organized in a prudent manner, it does not satisfy question about the current acceptable opinions about it. However, the reader as a result faces some pertinent questions in this area of study which may be connected through indirect evidence. The reader as a result may be inclined to examine the concepts of immunity, allergy, or biofilm hypothesis more closely through further research which may unravel the truth. From that perspective, it is very justified to accept this article for publication. Reference Bollinger, RR., Barbas, AS., Bush, EL., Lin, SS., and Parker, W., (2007). Biofilms in the large bowel suggest an apparent function of the human vermiform appendix. Journal of Theoretical Biology; 249: 826-831 Read More