The Lymphatic & Immune System Malena Boome Lauren Helmer Iker Lopez Anatomy, period 3 Presentation date: 4/11/13

Introduction The lymphatic system is closely associated with the cardiovascular system. The 3 main functions: Transports excess fluid to the blood stream Absorbs fats Helps defend the body against disease- causing agents.

Major Organs & Lymphatic Pathways Major organs: Heart, lungs, intestines, liver, and skin have lymphatic vessels. The brain, however, has no lymphatic vessels Lymphatic capillaries: microscopic, close-ended tubes that extend to interstitial spaces Lymphatic vessels: thinner walls than those of veins, possess valves that prevent back flow of lymph

Lymphatic vessels transporting fluid to interstitial spaces to the bloodstream

Location of Major Lymphatic pathways Larger lymphatic vessels lead to lymph nodes, then merge into lymphatic trunks. These trunks lead into 2 collecting ducts: the thoracic duct and the right lymphatic duct.

Lymph & Tissue Fluid Tissue fluid originates from blood plasma As the protein concentration of tissue fluid increases, colloid osmotic pressure increases Increasing pressure within interstitial spaces forces some tissue fluid into lymphatic capillaries, and that fluid turns into lymph Lymph: returns protein molecules to the blood stream and transports foreign particles to lymph nodes

Lymph Nodes Subdivided into nodules that contain phagocytes and macrophages Lymph nodes collect along the paths of larger lymphatic vessels Functions: Filter potentially harmful foreign particles from lymph Centers for the production of lymphocytes & contain phagocytic cells

Thymus & Spleen Thymus: an organ composed of lymphatic tissue divided into lobules that shrinks after puberty Function: lymphocytes leave the thymus and provide immunity Spleen: an organ resembling a large lymph node that’s subdivided into lobules that contains macrophages. Function: The macrophages filter foreign particles and damaged red blood cells from blood

Body Defenses Against Infection The body has innate (nonspecific) and adaptive (specific) defenses against infection. Innate and adaptive defense mechanisms work together to protect the body against infection. Innate defenses respond rapidly, adaptive defenses which are slower to respond, still begin as well.

Innate Defenses Species resistance Mechanical Barriers A given kind of organism, or species develops a set of diseases that is unique to it. Mechanical Barriers The skin and mucous membranes lining the passageways of the respiratory, digestive, urinary, and reproductive systems. Chemical Barriers Enzymes in body fluids provide a chemical barrier to pathogens. Fever Elevated body temperature due to fever offers powerful protection. Inflammation A tissue response to injury or infection, producing localized redness, swelling, heat, and pain. Phagocytosis Bloods most active phagocytic cells are neutrophils and monocytes.

Adaptive Defenses, or Immunity Antigens Before Birth, body cells inventory “self” proteins and other large molecules. After inventory, lymphocytes develop receptors that allow them to differentiate between nonself (foreign) and self antigens. Lymphocyte Origins Lymphocytes originate in red bone marrow and are released into the blood before they differentiate. Lymphocyte Functions Some T cells interact with antigen- bearing agents directly, providing the cellular immune response. T cells secrete cytokines, such as interleukins, that enhance cellular responses to antigens. B cells interact with antigen-bearing agents indirectly, providing the humoral immune response.

Adaptive Defenses, or Immunity (continued). T Cells and Cellular Immune Response T cells are activated when an antigen-presenting cell displays a foreign antigen. When a macrophage acts as an accessory cell, it phagocytizes an antigen- bearing agent, digest the agent, and displays the antigens on its cell membrane in association with certain MHC proteins. B Cells and the Humoral Immune Response A B cell is activated when it encounters an antigen that fits its antigen receptors. An activated B cell proliferates, enlarging its clone. Some activated B cells specialize into antibody- producing plasma cells. Antibodies react against the antigen- bearing agent that stimulated their production. An individuals diverse B cells defend against a very large number of Pathogens. Types of Antibodies Antibodies are soluble proteins called immunoglobulin's.

Types of Antibodies (continued). Immunoglobulin G (IgG) IgG is in plasma and tissue fluids and is particularly effective against bacteria, viruses, and toxins. Immunoglobulin A (IgA) Commonly found in exocrine gland secretions. It is in breast milk, tears, nasal fluid, gastric juice, intestinal juice, bile, and urine. Immunoglobulin M (IgM) Develops in the blood plasma in response to contact with certain antigens in food or bacteria. Types of antibodies that are IgM are –anti- A and anti-B. Also activates complement. Immunoglobulin D (IgD) Found on the surfaces of most B cells, especially those of infants. It is important in activating B cells. Immunoglobulin E (IgE) Appears in exocrine secretions along with IgA. It is associated with allergic reactions.

Adaptive Defenses or Immunity (continued). Antibody Actions Antibodies directly attach to antigens, activate complement or stimulate local tissue changes that are unfavorable to antigen-bearing agents. Direct attachment results in agglutination, precipitation, or neutralization. Activated proteins of complement attract phagocytes, alter cells so that they become more susceptible to phagocytosis, and rupture foreign cell membranes (lysis). Immune Responses The first reaction to an antigen is called a primary immune response. During this response, antibodies are produced for several weeks. Some B cells remain dormant as memory cells. A secondary immune response occurs rapidly as a result of memory cells response if the same antigen is encountered later. Practical Classification of Immunity Naturally acquired immunity arises in the course of natural events, whereas artificially acquired immunity is the consequence of a medical procedure. Active immunity lasts much longer than passive immunity. A person who encounters a pathogen and has a primary immune response develops naturally acquired active immunity. A vaccine produces another type of active immunity. A person who receives an injection of antibodies (vaccine) has artificially acquired passive immunity.

Adaptive Defenses or Immunity (continued). Allergic Reactions Allergic reactions are excessive and misdirected immune responses that may damage tissue. They are classified by how quickly they follow exposure to the allergen. Delayed-reaction allergy, which can occur in anyone and inflame the skin, results from repeated exposure to antigens. After the repeated exposure, the presence of foreign substances activates T cells. Immediate-reaction allergy is an inborn ability to overproduce IgE. The reaction happens within minutes of contact from the allergen. The immediate reaction allergy activates B cells, which become sensitized when the allergen is first encountered. Allergic reactions are triggered. In the initial exposure, IgE attaches to the membranes of widely distributed mast celled and basophils. When a subsequent allergen-antibody reaction occurs, these cells release allergy mediators such as histamine, prostaglandin D2, and Leukotriene's. mast cells bursting an releasing allergy mediators such as histamine. The released chemicals cause allergy symptoms such as hives, hay fever, asthma, eczema, or gastric disturbances.

Adaptive Defenses or Immunity (continued). Transplantation and Tissue Rejection Transplantation of tissues or an organ, such as the skin, kidney, heart, or liver, from one person to another can replace a nonfunctional, damaged, or lost body part. A transplant recipient’s immune system may react against the donated tissue, an event termed a tissue rejection reaction. Matching donor and recipient tissues and using immunosuppressive drugs can minimize tissue rejection. These drugs interfere with the recipient’s immune response by suppressing formation of antibodies or production of T cells, thereby dampening the humoral and cellular immune responses. Immunosuppressive drugs may increase susceptibility to infection. A heart lasts 3 to 5 hours outside the body before needing to be transplanted, a liver lasts 10 hours, and a kidney lasts 24-48 hours.

Adaptive Defenses or Immunity (continued). Autoimmunity In autoimmune disorders, the immune system manufactures autoantibodies that attack a person’s own body tissues. Autoimmune disorders may result from a previous viral infection, faulty T cell development, or reaction to a nonself antigen that resembles a self-antigen.

Diseases/ Disorders AIDS Lymphoma Autoimmunity Human immunodeficiency virus causes AIDS. Gradually shuts down the immune system. Lymphoma Tumor composed of lymphatic tissue. Autoimmunity Immune system manufactures auto antibodies that attack a person’s own tissues.

Work’s Cited Page Oakes, David D. "Thymus." World Book Advanced. World Book, 2013. Web.  19 Mar. 2013.  Land, Michael H. "Immune system." World Book Advanced. World Book, 2013. Web.  19 Mar. 2013.  Schmid-Schoenbein, Geert W. "Lymphatic system." World Book Advanced. World Book, 2013. Web.  19 Mar. 2013.  Shier, David, Jackie Butler, and Ricki Lewis. Hole's Essentials of Human Anatomy and Physiology. 9th ed. Boston, Burr Ridge, IL, Madison, WI, New York, San Francisco: tion, 2006. 360-381. Print.