The Capacity to Defend the Human Body against Diseases - Coursework Example

Immune System Department Immune system The human body has the capa to defend itself against diseases or infections from the outside environment. This paper is a report on the immune system and focuses on non-specific defences of the body against infectious disease, and specific defences against diseases. The mechanical and chemical non-specific defences, inflammation and phagocytosis against disease are also covered in this paper. Non-specific and specific defences are referred to as natural defences. According to Fullick (1998:27), "The human body has a number of lines of defence against the invasion of pathogens. Our defences can be considered in two parts-the non-specific defences and the specific immune system". The three lines of defence against disease Before elucidating non-specific and specific mechanisms of defence, it is imperative to note that there are three lines of defence against disease causing microorganisms in the body. The first line of defence according to Wikibooks Contributors (2006) involve locking alien maters or attacker outside the body and this function is attained by the skin and mucous membranes. The second line of defence is now what is referred to as the non-specific mechanism of defence and deals with pathogens that have managed to pass through the first line of defence. The third line of defence include the specific mechanisms and comprises of actions by B lymphocytes to produce antibodies and T-cells to help the antibodies destroy antigens or alien substances. Non-specific defences Stainton et-al (2009) in their book Tabbners Nursing Care: Theory and Practice categorises Non-specific defences into two main groups namely external and internal defences. Additionally, Stainton et-al (2009: n.d) asserts that "external defences are the mechanical and chemical barriers that protect the potential entry points invasion by microorganisms. Internal defences are the automatic protective actions of the inflammatory process, phagocytic cells, natural killer cells and protective proteins". Example of a mechanical defence is the skin. It is worth noting that the non-specific defences include components and activities involved in the normal functioning of the body and examples include the skin, blood clotting, inflammation, and gut. The skin is the outer layer or covering of the body that physically blocks microorganisms from entering the body (Russell, Hertz and McMillan, 2011). There is also a chemical manufactured by the skin referred to as sebum and this hampers the development of bacteria, viruses, and other germs on the skin. This chemical has the capacity to subsist on the skin devoid of negatively affecting it. There are also un-harmful microorganisms that live permanently on the skin and these helps in averting other disease causing organisms from attacking the body. Other parts of the body such as the small intestines similarly possess a defensive or protective layer that is comparable to the skin. Some organs in the body such as the nose and ears have mucous membranes that trap pathogens and hence prevents them from entering the body (Stainton et-al, 2009). Germs can also find their way in to the body of an individual through cuts or injured parts of the body. Examples of germs that can enter through cuts include herpes virus, and tetanus causing organisms. Certain insects such as mosquitoes have the ability to perforate the skin in a bid to suck blood and in doing so, they can deposit diseases causing organisms in the body. Once the body is injured, its first reaction is to close up the injured or cut section. This process is referred to as blood clotting. There are also other chemical substances produced by different body organs that help remove pathogens from the body. For instance, the eyes produce tears comprising of enzymes with the capacity to exterminate microbes or germs (Russell, Hertz and McMillan, 2011). Subsequently, there are chemical substances produced by the digestive system and these obliterate disease causing microorganisms present in the food we eat. Inflammation Another technique the body fights infections is through a process referred to as inflammation. In definition, inflammation is an intercession or intervention reaction that takes place subsequent to the failure of the first line of defence to terminate a disease causing organism attacking the body. More blood is pumped into the injured part in a bid to confiscate and eradicate any contagions. The main aim of pumping more blood into the injured region is to dilute disease causing organisms and hence enabling the white blood cells to destroy them. More blood translates to more white blood cells attacking the disease causing organisms. As postulated by Moini (2013), inflammation is an effort by the body to segregate an injured section geared towards curtailing the distribution of pathogens to other parts of the body and at the same time allow the body to focus on that specific section to revamp it. Phagocytosis Phagocytes is another name for white blood cells. The main function of phagocytes in relation to defence against pathogens is to swallow and subsequently eliminate them. According to Whitney and Rolfes (2012: 583), "Phagocytes, the scavengers of the immune system, are the first to arrive at the scene if an invader, such as a microorganism, gains entry. Upon recognising the foreign invader, the phagocyte engulf and digests it, if possible, in a process called phagocytosis". Two kinds of white blood cells are involved in this process and these are neutrophils and macrophages. Whitney and Rolfes (2012) further posit that neutrophils comprise the majority of phagocytes and are in fact accountable to a great extent on defending the body against pathogens. Macrophages on the other hand act at a smaller velocity and are capable of swallowing up bigger pathogens as compared to neutrophils. Specific mechanisms Rosdahl and Kowalski (2003: 286) brings forward the fact that specific mechanisms of defence are "considered the final line of defence against disease. Humoral and cell-mediated immunity are considered specific defence mechanisms because they act against particular harmful substances". Non-specific mechanisms of defence deals with pathogens or disease causing microorganisms that have not yet entered the body. Some of the pathogens are able to find their way into the body and hence specific mechanisms of defence take over from the non-specific mechanisms to protect the body against these pathogens. To understand how the specific mechanism of defence works, it is important to define some terms. An antigen is a scientific term denoting any alien or unknown matter attacking the body. Immediately the body detects the presence of an unknown matter, a number of cells involved in this identification prompt B lymphocytes to manufacture and release antibodies. These generated antibodies lock together with the antigens. Specific antibodies generated by the B lymphocytes as a result of an attack by an alien matter are maintained within the particular individuals body permanently. This is important to the body in case there is an attack by a similar alien matter as the antibodies will already be present to deal with the alien matter without the B lymphocytes producing more antibodies. Immunisations acts in a similar manner (Srivastava, 2003). An immunisation is an introduction of an alien matter into the body which in return prompts the B lymphocytes to manufacture antibodies. In doing so, antibodies are introduced in the body permanently and lays in wait for specific pathogens to attack and subsequently obliterates them. It is however worth elucidating the fact that antibodies cannot destroy alien matters in the body without the assistance of cells referred to as T-cells. These T-cells are also important in the whole process as they gesture or prompt other protective cells to conduct their functions (Srivastava, 2003). Conclusion There are three lines of defence against diseases in the body. First line of defence involve the skin and mucous membranes, second line of defence include the non-specific mechanisms such as inflammation and phagocytosis, while the third line of defence involves specific mechanisms of defence that include the activities of B lymphocytes that produces antibodies and T-cells which are the killer cells. Non-specific mechanisms are divided into internal and external mechanisms. External mechanisms include the mechanical and chemical defences against pathogens. An example of mechanical defence include the skin while that of a chemical defence include tears produced by the eyes that have enzymes that kill pathogens. Internal mechanisms include inflammation and phagocytosis. Specific mechanisms on the other hand involve the action of antibodies on antigens. Introduction of an alien matter in the body activates the manufacture and release of antibodies by B lymphocytes and these lock the antigens. References Fullick, A. (1998) Human Health and Disease. Portsmouth: Heinemann Educational Publishers. Moini, J. (2013) Introduction to Pathology for the Physical Therapist Assistant. Burlington: Jones & Bartlett Learning. Rosdahl, C.B., & Kowalski, M. T. (2003) Textbook of Basic Nursing. London: Lippincott Williams & Wilkins. Russell, P., Hertz, P., & McMillan, B. (2011) Biology: The Dynamic Science, Volume 3, Units 5 & 6. Belmont: Cengage. Srivastava, S. (2003) Understanding Bacteria. Donrdrecht: Kluwer Academic Publishers. Stainton, K., Hughson, J., Funnel, R., Koutoukidis, G., & Lawrence, K. (2009) Tabbners Nursing Care: Theory and Practice. Chatswood: Elsevier. Whitney, E., & Rolfes, S.R. (2012) Understanding Nutrition. Belmont: Wadsworth. Wikibooks Contributors. (2006) Human Physiology. Birmingham: Wikibooks Publishers. Read More