Module 04 Lab Worksheet: Lymphatic and Immune Systems Introduction
This week’s lab will focus on understanding the concepts of the lymphatic and immune system’s ability to protect and defend our body from foreign pathogens and assist in maintaining homeostasis. Objectives Objectives for this week’s lab include: 1) Compare and contrast innate and adaptive defenses, 2) Compare and contrast the various forms of adaptive defenses, and 3) Perform ELISA tests on simulated patients. Overview The lymphatic and immune systems play a vital role in our body’s ability to defend itself from pathogens- biological agents that can cause harm, illness and/or disease to its host. The immune system is technically not an organ system but rather a collection of barriers, proteins and immune cells that reside throughout the entire body but are concentrated within the lymphatic system. The lymphatic system’s primary role is to collect fluid that has leaked out of the capillary vessels, mainly plasma components, filter the fluid and return it back to the circulatory system (blood). It is composed mainly of three components: Lymphatic vessels, lymph, and lymph nodes. The lymphatic system also consists of lymphatic organs and tissues such as the spleen and thymus. Fluid that is lost from capillary blood vessels due to osmotic pressure, is “soaked” up by the permeable lymphatic vessels that found throughout the body and interweave with tissues and capillary beds. The fluid inside the lymphatic vessels is then referred to as lymph fluid, which is very similar to the composition to the plasma of blood. The lymph fluid is ultimately returned back to the circulatory bloodstream to maintain proper blood volume, but first the lymph fluid is filtered and “cleaned up”. The lymphatic vessels transport the lymph nodes, which are the primary and most numerous lymphatic organ. Lymph nodes are found all throughout the body but are concentrated in specific regions of the body, such as the axilla and neck. The lymph nodes serve two basic functions: 1. Filter the lymph fluid by removing any pathogens (particularly microorganisms) and any other cellular debris, and 2. Allow for quick activation of the immune system cells if a foreign antigen is detected. The immune system, as stated before, is technically not a true organ system but rather a collection of barriers, proteins and immune cells found throughout our body to provide a means of resistance and recovery to disease. The immune system can be divided into two intrinsic defense mechanisms: Innate (non-specific) and adaptive (specific) defenses. Our innate defenses can be classified as either- surface barriers, such as the skin, or internal defenses, such as inflammation and fever. The innate defenses do not require prior exposure to a pathogen to effectively defend our body from pathogens. From the first exposure to a specific pathogen and onward, our innate defenses will provide effective and immediate protection (only to the defenses ability) to that pathogen or any other. The adaptive defenses are classified as humoral immunity (B-cells) and cellular immunity (T cells) and depend on prior exposure to effectively defend our body from pathogens. The adaptive defenses, when functioning properly, will defend our body from a wide range of infectious agents, abnormal body cells such as cancer and any other harmful agents. There are three vital points to our body’s adaptive defenses: 1. Specificity- it recognizes and targets specific antigens, 2. Systemic- the immune response is not localized to the initial infection site, 3. Memory- it creates a specific memory to a particular antigen; allowing for a quicker and stronger response on future exposure. Humoral immunity consists of B-lymphocytes that ultimately produce antibodies that are specific to one type of antigen, which circulate freely throughout the blood and lymph.Antibodies block and tag an antigen for destruction by other immune cells. Cellular immunity consists of T-lymphocytes that ultimately produce cytotoxic T cells that directly destroy specific antigens within the body. Materials · ELISA test kits · Markers/color pencils of various colors · Large Post-It pads or presentation paper · Lancets · Microscope slide · Band-Aids · Alcohol wipes · Toothpicks Pre-Lab Evaluation Questions The pre-lab evaluation questions must be answered prior to lab and demonstrated to your lab instructor. You must read through the assigned chapter readings, lab introduction, objectives, overview and procedure to answer these questions. Please cite your work for any reference source you utilize in answering these questions. 1. In your own words: What is an antigen? What is antigenic determinant/epitope? What is an antibody? What is an antigen-antibody interaction/reaction? 2. How do antibodies in our body function to provide protection against pathogens? 3. Briefly compare and contrast innate and adaptive body defenses? 4. In your words, briefly describe the difference between humoral and cellular adaptive body defenses. 5. What is the ELISA test and how does it work? Part 01 Procedure: Innate and Adaptive Body Defenses 1. Working in your lab groups, you will be tasked with presenting 1-3 of these six topics to the class: a. Explain the difference between innate and adaptive body defenses. b. Explain how the adaptive body processes work, the difference between the two types of adaptive body processes. c. Using the concepts of primary adaptive responsive and secondary adaptive response, explain how vaccines work. d. Explain how the ELISA test works. e. Explain the signs and role inflammation has within our body. f. Compare and contrast the following immune disorders: immunodeficiency, hypersensitivity, and autoimmune immunity. 2. Your groups will have access to markers, large Post It pads and your creativity to design your presentations to present to class. This is a group effort and everyone will be expected to participate. Part 02 Procedure: ELISA Testing 1. Your lab groups will be performing ELISA tests on ten different patients to determine their HIV status. 2. Working in groups of 2-4, follow the instructions provided by your lab instructor on how to perform the ELISA test for each patient. 3. Fill in the chart to track each patient’s results with the diagnosis: Well Number Patient Test Result Observations 1 Negative Control 2 Low Positive Control 3 High Positive Control 4 Jan 5 Lynn 6 Baby Elizabeth 7 Roger 8 Bob 9 Tony 10 Richard 11 Tania 12 William Part 03 Procedure: Agglutination of Blood 1. This portion of the lab will consist of two lab group members performing individual finger pricks to draw blood and mixing the blood together to observe antigen and antibody reactions. Universal precautions will be observed and demonstrated by all students during this procedure. 2. Gather the appropriate equipment for this portion of the lab: Lancet for each individual performing the finger prick, a microscope slide, a toothpick, alcohol wipes, and Band-Aids. 3. Following the finger prick procedure from Module 01 Laboratory assignment, each individual should provide one drop of blood on the microscope slide. Try to get the drops of blood close to one another but without touching. 4. Another member will mix the two blood drops together with the toothpick and record any observations you see. There might be the random chance that each group member that provided the blood drop may have the same exact blood type, so it may have to be performed by a few different individuals. 5. Record any observations you see below: Post-Lab Evaluation Questions The post lab evaluation questions must be completed prior to your submission of the lab. Answers for these questions will be derived from the lab protocol, the weekly concepts associated with the lab and possibly research content from the book and/or online resources. Please cite your work for any reference source you utilize in answering these questions. 1. What did you learn or gain from the presentations you worked on in your group and/or from the other groups presenting about the specific topics? 2. A lot of individuals get the influenza vaccine each year but it is highly recommended for the young and elderly. Why is this the case? Why do some people who get the influenza vaccine still come down with the flu? 3. Why isn’t there a vaccine for the common cold but one for chicken pox virus (Varicella Zoster vaccine)? 4. What role do the lymph nodes have within the lymphatic system? How does it allow for activation of immune system cells? Lastly, how does metastatic cancer pertain to the lymphatic system and lymph nodes? 5. Compare and contrast the differences with immunodeficiency, hypersensitivity and autoimmune disorders including the basic treatments for each type.
