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Human Anatomy and Physiology: AIDS
Explain How the Pathogen for Aids Is Able to Cause Diseases and How the Body’s Immune System Responds to It.
The body of a human being is prone to attack by organisms that are known to cause diseases. To counter these organisms and also enable the body to carry out its daily activities, the human body is incorporated with an immune system that helps it fight the disease-causing microorganisms. The immune system is made up of many distinct elements which include the proteins and cells among others. The immunes system is second after the nervous system in terms of complication and is identified to have many functions, but the primary one is to identify and detect microorganisms that cause diseases. The second function carried out by the immune system is to combat cells that have been transformed by the disease causing microorganisms. In this regard, the immune system carries out different functions to ensure the safety of an individual.
Demonstrate an Understanding of the Human Immune System in the Defense Against Pathogens.
The human immune system is able to work based on the concept that the body is able to differentiate and recognize itself and the invaders. Generally, pathogens take different forms, ranging from bacteria, parasites, and viruses. The human immune system uses a variety of tactics in dealing with the pathogens once the body has identified them (Medline Plus, 2017). Some of the components making up the immune system include the lymph nodes, the thymus, the bone marrow, the spleen, and the lymphocytes.
The function of the lymph nodes is to produce and store cells that fight diseases and infections. The lymph nodes also produce some fluid that takes these cells in the different parts of the body. Equally important, the nodes also filter the special cells from the fluid they produce (Medline Plus, 2017). The function of these special cells is to trap cancerous cells and other bacteria that a person’s body through the lymph fluid. The significance of lymph nodes in the human immune system is attributed to the fact that they are the genesis of human immune reactions. The other organ critical to the role of the immune system is the thymus where T-cells are produced and mature (Medline Plus, 2017). The third organ is the spleen, which is also identified as the largest lymphatic organ. The organ serves many purposes, with the first one being that they store the white blood cells that fight diseases and other infections. The organ also assists in destroying damaged and old cells, as well as controlling the amount of sugar in the blood. The other primary organ of the immune system is the bone marrow, whose main function is to produce the white blood cells which later become the lymphocytes (Medline Plus, 2017). The lymphocytes play the largest role in ensuring the body is defended from diseases. The are two types of lymphocytes, the T-cells and the B-cells (Medline Plus, 2017). The role played by the B-cells is to produce antibodies that attack the toxins and bacteria invading the body. The T-cells on the other hand assists in the destruction of cancerous or cells that have already been infected (Medline Plus, 2017). They also help in attacking the body cells that have been taken over by other viruses, or those that have already become cancerous.
Action of the Immune System
 When the immune system is invaded by a virus, the body activates some specific immune processes. The first process is the identification of the foreign antigen, where it is then taken to the lymph system for ingestion by the macrophage. The antigens hosted by that particular virus are exposed and the T-cell is signaled (Medline Plus, 2017). Upon receiving the signal, the T-cells alarm the other organs of the immune system to respond. The B-cells are activated and engage in the production of antibodies that are specific to the exposed antigen (Medline Plus, 2017). The antibodies engulf the antigens while sending signals to other cells of the immune system to enhance the engulfing and also destroy the entire antibody. The last stage of the immune response is comprised of the activities carried out by the T-cells (Medline Plus, 2017). The T-cells signals the other cells to rest once the pathogens have been reduced. Signaling other cells to rest is paramount as prolonged activation of the immune system may lead to damage of the healthy cells (Medline Plus, 2017).
How HIV Affects the Immune System
The HIV virus infects the human immune by altering the activities carried out by the T-cells. The initial immune system, that is, the B-cells and the macrophages are able to get rid of the HIV virus, but some of them are able to reach the T-cells (Healthline, 2017). On activating the already infected T-cells, they do not perform their initial duty but instead activates the proliferation of new viruses (Healthline, 2017). Noteworthy, T-cells that do not have any infection are destroyed when the HIV virus is increasing its presence in a patient’s body.
Human Defence Mechanisms to Harmful Pathogens
The human body reacts in two ways when it is infected by pathogens; through the use of first line of defense or through the second line of defense (Pirofski & Casadevall, 2012). The first line of defense is physical in nature and entails reactions such as sweating and the development or acid or mucus in the stomach. The mucous membranes and the skin are effective in keeping the pathogens from entering the body (Pirofski & Casadevall, 2012). That is, they are a protective barrier and capable of fairly keeping the pathogens from our bodies. For instance, no bacteria have the capability of penetrating the skin under normal conditions which are characterised by a pH that ranges from three to five (Pirofski & Casadevall, 2012). Such a range has enough acid to prevent the bacteria from growing. Additionally, a blood clot in wounds coagulates the blood in open wounds so as to prevent the antigens from entering the body. The specific mechanism is also identified as the second line of defence, which takes action when the invaders enter into the body of a human being (Pirofski & Casadevall, 2012). The invading virus or bacteria is ingested by blood cells, which could either be the white blood cells, the B-cells, or the T-cells (Pirofski & Casadevall, 2012).
A Healthy Immune System and Characteristics of Disease Causing Micro-Organisms
Some of the characteristics exhibited by most disease-causing microorganism include that they can either be multi-cellular, or single-celled, that is, some are made of one cell while others are made of many cells (Singh et al., 2014). The second characteristic shared by most of these cells is that they are all microscopic in that they are no visible using the naked eye. Therefore, to examine or conduct tests, doctors use microscopes to view and differentiate one bacterium from the other.   A healthy immune system is one in which the body of a human being is able to fight the antigens while at the same recognizing itself (Chaplin, 2010). In a healthy immune system, the antibodies are triggered by the presence of antigens. Accordingly, the antibodies fight the antigens and also maintain the healthy cells. Therefore, in a healthy immune system prevents the chance of a body fighting its own cells (Chaplin, 2010).
 
 
 
Reference List
Chaplin, D D, 2010, ‘Overview of the immune response’, Journal of Allergy and Clinical Immunology, 125 vol. no. 2, pp.S3-S23.
Healthline, 2017, ‘How HIV affects the body.’Available from http://www.healthline.com/health/hiv-aids/how-hiv-affects-the-body
Medline Plus, 2017, ‘Immune Response.’ Available from: https://medlineplus.gov/ency/article/000821.htm
Pirofski, LA &Casadevall, A, 2012,‘Q&A: What is a pathogen? A question that begs the point’BMC biology, vol. 10 no. 1, p.6.