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Instructions Research and identify an environmental or occupational toxicant that effects on the respiratory system. Research and discuss the following: Explain the normal function of the system and what makes it susceptible to toxicity. Describe how exposure to the toxicant is possible. Analyze the acute and/or chronic effects of the toxicant. Describe recent concerns about the toxicant (within the last two years) and any actions taken to reduce the toxicant in the environment or reduce occupational exposure to the toxicant. Your research paper should meet the following requirements: Address all of the above mentioned aspects in the discussion. The paper should be a minimum of three pages in length, not including title and reference pages. Utilize at least four credible references no more than five years old. Utilize proper APA formatting and citations. unitiv_study_guide.pdf u4_draft.docx Unformatted Attachment Preview UNIT IV STUDY GUIDE Toxic Effects on the Liver, Lungs, and Immune System Course Learning Outcomes for Unit IV Upon completion of this unit, students should be able to: 3. Explain biological processes related to the processing of toxins in the body. 3.1 Explain the normal functions of a body system and what makes the system susceptible to toxicity. 3.2 Describe how exposure to a toxicant is possible in a specific body system. 6. Assess the effects of various toxicants on body systems. 6.1 Analyze the acute and chronic effects of toxicants on body systems. Course/Unit Learning Outcomes 3.1 3.2 6.1 Learning Activity Unit Lesson Chapters 6, 10, and 11 Research Paper Unit Lesson Chapters 6, 10, and 11 Research Paper Unit Lesson Chapters 6, 10, and 11 Research Paper Reading Assignment Chapter 6: Hepatotoxicity: Toxic Effects on the Liver, pp.125-137 Chapter 10: Pulmonotoxicity: Toxic Effects in the Lung, pp.179-191 Chapter 11: Immunotoxicity: Toxic Effects on the Immune System, pp.197-202, 205-209 Unit Lesson This unit covers the topics of toxicology of the immune system, the respiratory system, and the liver. The immune system is the body’s primary defense mechanism against microorganisms. Core functions of the immune system include regulating the internal environment and recognizing and removing malignant cells (Roberts, James, & Williams, 2015). The immune system may produce two different types of responses: innate response and acquired response. An innate response, or natural immunity, includes various protective mechanisms of the body such as skin (physical barrier) or blood (chemical barrier) (Roberts et al., 2015). An acquired response is one that is established over a period of time as a result of multiple exposures. An acquired response can increase with successive exposures (Roberts et al., 2015). For example, someone with a developing allergy to peanuts may have a mild response to exposure such as itching or a mild rash. Upon successive exposures, the individual may one day experience anaphylaxis or a severe reaction to peanuts due to an increasing response over time. A variety of substances have been found to affect the immune system. A well-known virus that has received intense media coverage, research funding, and attention over the past 20-30 years is the human immunodeficiency virus, or HIV. The final stages of HIV are known as AIDS (acquired immune deficiency syndrome). The first cases of the then unknown illness were reported in the United States in June of 1981. More than 619,000 people with AIDS have died in the United States since the epidemic began (AIDS.gov, MOS 5425, Advanced Toxicology 1 2012). HIV is believed to have originated in West Africa and was spread to humans the consumption UNIT xbySTUDY GUIDE of chimpanzees that carried the virus. Once in the human body, the virus attacksTitle T-cells, or CD4 cells, and uses them to make copies of themselves. The virus has progressed to AIDS when the virus has destroyed too many of the body’s T-cells, and the immune system is weakened and susceptible to opportunistic infections (U.S. Department of Health and Human Services, 2012). HIV is one example of a toxicant that impacts the immune system. It is important to understand the major immunotoxicants as discussed in your textbook. Factors affecting the immune system include genetics, diet, exercise, and environmental toxin exposure. The textbook details numerous chemicals that can induce immunotoxicity. This is an extensive but not all inclusive list. Immunotoxicity may occur in many ways. Hypersensitive reactions occur when exposure to a chemical evokes an inappropriate or over-reaction, such as an allergic reaction by the normal immune system. An example of this may be an individual having an allergic reaction to pollen or an allergic reaction to penicillin. Immune suppression is another type of immunotoxicity. According to Luster and Rosenthal (1993), immunosuppression by chemical means has not been as well documented as hypersensitivity to chemicals has been. They further discuss that some chemicals such as asbestos, benzene, and halogenated aromatic hydrocarbons, which are considered occupational exposure, have been documented to result in immunosuppression. The textbook further reinforces the point that occupational and environmental exposure to chemicals has been suggested in lab studies to cause immunosuppression, but limited information in clinical studies is available to support the findings. The last type of immunotoxicity is autoimmunity. In simplest terms, autoimmunity is when an organism’s immune system attacks its own healthy cells, tissues, or organs. Some examples of agents that may cause autoimmunity include cadmium, which is used in the manufacturing of some batteries and as a stabilizer in plastics such as PVC pipes; mercury in thermometers and fluorescent lights; paraquat, which is used in pesticides; and sulfonamides, which are a category of antibacterial drugs commonly used to medically treat various infections (Roberts et al., 2015). The primary function of the respiratory system is to supply blood with oxygen to be delivered throughout the body. The respiratory system is made up of the organs and tissues that help you breathe (National Heart, Lung, and Blood Institute, 2012). Oxygen enters the body through the nose and mouth, travels through the larynx (voice box) and trachea (windpipe), and into the bronchial tubes of the lungs. Within the lungs, oxygen travels from the bronchial tubes to smaller tubes (bronchioles) that end in air sacs (alveoli). Each of these air sacs are covered in blood vessels (capillaries). Blood travels throughout the body using a network of arteries and veins to distribute blood-rich oxygen and remove carbon dioxide (National Heart, Lung, and Blood Institute, 2012). The lungs are commonly the target organ for exposure to many toxins and toxicants from the environment. Many toxicants are known to adversely affect the respiratory system in humans and animals. The main toxic inhalants are found in two forms. The first form is that of a gas such as nitrogen dioxide, ozone, and chloride. The second main form of toxic inhalants is that of airborne particles such as aerosols, dust, smoke, and smog (Roberts et al., 2015). The toxicants are delivered to the blood stream by the respiratory system, just as oxygen is, and are circulated by the blood to various parts of the body where the effects are felt, including gases such as general anesthesia. (COPD versus healthy lung, 2011) MOS 5425, Advanced Toxicology 2 Toxic inhalants can affect the respiratory system in an acute as well as chronicUNIT manner. SomeGUIDE toxic gases x STUDY may induce cell necrosis within the respiratory system. Other toxic substancesTitle may attract certain enzymes to accumulate in the respiratory system in an attempt to metabolize the foreign compound but cause injury to the area (Roberts et al., 2015). Some acute responses of the respiratory system to toxic inhalant injury include oxidative stress, hyperimmune response, alterations in airway function, and acute pulmonary edema (Roberts et al., 2015). Chronic responses are long-term effects, often taking an extended period of time to develop. Examples of this type of response include many pulmonary ailments/diseases such as development of chronic obstructive pulmonary disease (COPD), pulmonary edema, asthma, silicosis, and lung cancer. The liver is the largest and metabolically the most complex organ in the body. It is involved in the metabolism of nutrients and detoxification of substances in the body. Most toxicants enter the body via the gastrointestinal tract, and after absorption, they are carried by the hepatic portal vein to the liver. The toxicology of the liver is complicated by the variety of liver injuries and by the different mechanisms through which the injuries are induced. The liver is often the target organ for chemical injury (Roberts et al., 2015). Several factors make the liver susceptible to toxicity. The first is that the liver filters blood coming from the gastrointestinal tract, meaning any drugs or chemicals that are absorbed by the gastrointestinal tract go directly to the liver. The liver is the first organ that these chemicals come in contact with, so often the toxicant is at its highest concentration before being filtered through the liver (Roberts et al., 2015). Another factor that makes the liver susceptible to toxicity is that it is the main site of biotransformation. Biotransformation is the reaction that takes xenobiotics and turns them into a form that can be more readily excreted. Toxicants can induce a variety of toxic effects on different organelles in the cells of the liver and exhibit different types of liver injuries. Both acute and chronic injuries may occur in the liver. Hepatotoxicants can target and affect various organelles within the liver cells, which may or may not lead to the death of the cells (Roberts et al., 2015). Liver necrosis may occur when the cells are unable to recover from injury. Many visible changes can indicate signs of necrosis such as swelling of the cell, breaks in the plasma membrane, and formation of cell fragments (Roberts et al., 2015). Examples of types of liver injury include hepatocellular degeneration and death, lipid peroxidation where free radicals are produced, irreversible binding to macromolecules leading to loss of function of liver cells, and loss of calcium homeostasis that regulates many processes in the liver. More commonly known types of liver injury include production of fatty liver, which can often be a result of excessive alcohol use; cholestasis, which is the decrease in bile flow; and cirrhosis, which is the increase in collagen fibers that can lead to fibrosis and tumor formation (Roberts et al., 2015). References COPD versus healthy lung. [Image]. (2011). Retrieved from https://commons.wikimedia.org/wiki/File:Copd_versus_healthy_lung.jpg Luster, M. I., & Rosenthal, G. J. (1993). Chemical agents and the immune response. Environmental Health Perspectives, 100. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1519592/ National Heart, Lung, and Blood Institute. (2012). Explore how the lungs work: The respiratory system. Retrieved from www.nhlbi.nih.gov/health/health-topics/topics/hlw/system.html Roberts, S. M., James, R. C., & Williams, P. L. (2015) Principles of toxicology: Environmental and industrial applications (3rd ed.). Hoboken, NJ: Wiley U.S. Department of Health & Human Services, AIDS.gov [AIDS.gov]. (2012). U.S. statistics. Retrieved from http://aids.gov/hiv-aids-basics/hiv-aids-101/statistics/ MOS 5425, Advanced Toxicology 3 Learning Activities (Nongraded) UNIT x STUDY GUIDE Title Nongraded Learning Activities are provided to aid students in their course of study. You do not have to submit them. If you have questions, contact your instructor for further guidance and information. Review Questions Upon completing the assigned reading from the textbook, you should be able to discuss the following key questions. Take some time to review the assigned reading if you cannot recall the answers to the following questions. 1. 2. 3. 4. 5. 6. 7. 8. What is the function of the liver, and why is it susceptible to injury? Describe key morphological changes that indicate injury has occurred in the liver. Identify three chemicals that can cause hepatotoxicity. What organs and structures are involved in the respiratory system? Discuss the two main types of toxic inhalants, and provide two examples of each. Give two examples of acute and chronic responses to respiratory system injuries. Explain some common immune reactions and disorders. Identify three chemicals that adversely affect the immune system, and discuss their effects. MOS 5425, Advanced Toxicology 4 Instructions Research and identify an environmental or occupational toxicant that effects on the respiratory system. Research and discuss the following: 1. Explain the normal function of the system and what makes it susceptible to toxicity. 2. Describe how exposure to the toxicant is possible. 3. Analyze the acute and/or chronic effects of the toxicant. 4. Describe recent concerns about the toxicant (within the last two years) and any actions taken to reduce the toxicant in the environment or reduce occupational exposure to the toxicant. Your research paper should meet the following requirements: 1. Address all of the above mentioned aspects in the discussion. 2. The paper should be a minimum of three pages in length, not including title and reference pages. 3. Utilize at least four credible references no more than five years old. 4. Utilize proper APA formatting and citations. ... Purchase answer to see full attachment