Lymphatic System PDF

Lymphatic System Copyright © McGraw-Hill Education. Permission required for reproduction or display. Functions of the Lymphatic System 1. Fluid balance 2. Fat Absorption 3. Defense Copyright © McGraw-Hill Education. Permission required for reproduction or display. ...

Lymphatic System Copyright © McGraw-Hill Education. Permission required for reproduction or display. Functions of the Lymphatic System 1. Fluid balance 2. Fat Absorption 3. Defense Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Figure 14.1 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Figure 14.2 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Components Lymph: fluid that enters lymphatic capillaries composed of water and some solutes Lymphocytes Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Lymphatic vessels Lymph nodes Tonsils Spleen Thymus gland Lymphatic Capillaries and Vessels Carries fluid in one direction from tissues to circulatory system (lymph flows only toward the heart) Fluid moves from blood capillaries into tissue spaces Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Lymphatic capillaries: - tiny, closed-ended vessels - fluid moves easily into - in most tissues - join to form lymphatic vessels Lymphatic vessels: - resemble small veins - where lymphatic capillaries join - one-way valves Right lymphatic duct: - where lymphatic vessels from right upper limb and right head, neck, chest empty Copyright © McGraw-Hill Education. Permission required for reproduction or display.  - empties into right subclavian vein Thoracic duct: - rest of body empties from lymphatic vessels - empties into left subclavian vein Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Lymphatic Organs Tonsils: - palatine tonsils on each side of oral cavity - pharyngeal tonsils near internal opening of nasal cavity (adenoid) - lingual tonsils posterior surface of tongue - form a protective ring of lymphatic tissue around nasal and oral cavities Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Figure 14.3 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Lymph nodes: - rounded structures that vary in size - located near lymphatic vessels - groin, armpit, neck - lymph passes through lymph nodes before entering blood - lymph moves through and immune system is activated (lymphocytes produced) if foreign substances are detected - removal of microbes by macrophages Figure 14.4 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Spleen: - size of clenched fist - located in abdomen - filters blood - detect and respond to foreign substances - destroy old red blood cells - blood reservoir - white pulp: lymphatic tissue surrounding arteries - red pulp: contains macrophages and red blood cells that connect to veins Figure 14.5 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Thymus gland: - bilobed gland - located in mediastinum behind the sternum - stops growing at age 1 - at age 60 decreases in size Copyright © McGraw-Hill Education. Permission required for reproduction or display. - produces and matures lymphocytes Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Figure 14.6a Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Immunity What is it? - ability to resist damage from foreign substances - Ex. Microbes, toxins, cancer cells Types of immunity: - innate - adaptive Copyright © McGraw-Hill Education. Permission required for reproduction or display.  First Line of Defense The first barrier to infection is unbroken skin and mucosal membrane surfaces. Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Secretions are also an important component in the first line of defense against microbial invasion. Immunoglobulin A (IgA) antibody is another important protective substance in tears and saliva. Copyright © McGraw-Hill Education. Permission required for reproduction or display. Second Line of Defense: Natural Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Immunity Inborn or innate resistance is one of the ways that the body resists infection after microorganisms have penetrated the first line of defense. is characterized as a nonspecific mechanism The elements of natural resistance include phagocytic cells, complement, and the acute inflammatory reaction. Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Third Line of Defense: Adaptive Immunity Acquired, or adaptive, immunity is a more recently evolved mechanism that allows the Copyright © McGraw-Hill Education. Permission required for reproduction or display. body to recognize, remember, and respond to a specific stimulus, an antigen. Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Humoral-Mediated Immunity specific antibodies have been formed to antigenic stimulation that confers immunity Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Antibody mediated immunity to infection can be acquired if the antibodies are formed by the host or if they are received from another source; these two types of acquired immunity are called active immunity and passive immunity, respectively. Active immunity acquired by natural exposure in response to an infection or natural series of infections Copyright © McGraw-Hill Education. Permission required for reproduction or display.  or through intentional injection of an antigen (vaccination) Passive immunity achieved by the infusion of serum or plasma containing high concentrations of antibody or lymphocytes from an actively immunized individual Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Cell-Mediated Immunity consists of immune activities that differ from antibody-mediated immunity moderated by the link between T lymphocytes and phagocytic cells (i.e., monocytesmacrophages) Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Innate Immunity What is it? - present at birth - defense against any pathogen - accomplished by physical barriers, chemical mediators, cells, inflammatory response Physical Barriers First line of defense Skin and mucous membranes to act as barriers Tears, saliva, urine wash away pathogens Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Chemical Mediators What are they? chemicals that can kill microbes and prevent their entry into cells Lysozyme: found in tears and saliva to kill bacteria Mucous membranes: prevent entry of microbes Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Histamine: promote inflammation by causing vasodilation Interferons: proteins that protect against viral infections by stimulating surrounding cells to produce antiviral proteins Cells White blood cells: produce in red bone marrow and lymphatic tissue that fight foreign substances Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Phagocytic cells: - ingest and destroy foreign substances - Ex. neutrophils and macrophages Neutrophils: first to respond to infection but die quickly Macrophages: - monocytes - leave blood and enter tissues - can ingest more than neutrophils Copyright © McGraw-Hill Education. Permission required for reproduction or display.  - protect lymph in lymph nodes and blood in spleen and liver - given specific names for certain areas of body (Kupffer cells in liver) Basophils: - made in red bone marrow - leave blood and enter infected tissues - can release histamine Mast cells: - made in red bone marrow Copyright © McGraw-Hill Education. Permission required for reproduction or display.  - found in skin, lungs, gastrointestinal tract, urogenital tract - can release leukotrienes Eosinophils: - produced in red bone marrow - release chemicals to reduce inflammation Natural Killer Cells: - type of lymphocyte - produce in red bone marrow Copyright © McGraw-Hill Education. Permission required for reproduction or display.  - recognize classes of cells such as tumor cells or virus infected cells - release chemicals to lysis cells Inflammatory Response What is it? - involves chemical and cells due to injury - signaled by presence of foreign substance - stimulates release of chemical mediators Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Figure 14.8 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Adaptive Immunity What is it? - defense that involves specific recognition to a specific antigen - acquired after birth - reacts when innate defenses don’t work - slower than innate immunity - has memory - uses lymphocytes (B and T cells) - 2 types antibody-mediated and cellmediated Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Terms Related to Adaptive Immunity Antigen: - substance that stimulates immune response - Ex. Bacteria, virus, pollen, food, drugs, etc. Self-antigen: molecule produced by person’s body that stimulates immune system response Antibody: proteins the body produces in response to antigen Origin and Development of Lymphocytes Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Stem cells: - red bone marrow - give rise to all blood cells - give rise to some pre T cells and pre B cells Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Lymphocytes: - type of white blood cell - involved in adaptive immunity - develop from stem cells - differentiate into specific lymphocytes such as B or T cells 48 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  B cells: - type of lymphocytes - involved in antibody-mediated immunity - originate from stem cells - mature in red bone marrow - move to lymphatic tissue after mature 49 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  - lead to production of antibodies T cells: - type of lymphocyte - involved in cell-mediated immunity primarily and antibody-mediated immunity - mature in thymus gland 50 Copyright © McGraw-Hill Education. Permission required for reproduction or display. - move to lymphatic tissue after mature - 4 types 51 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Figure 14.9 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Antigen Recognition Lymphocytes have antigen receptors on their surface Called B-cell receptors on B cells and T-cell receptors on T cells Each receptor only binds with a specific antigen When antigen receptors combine with antigen the lymphocyte is activated and adaptive immunity begins Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Major histocompatibility complex molecule (MHC): - contain binding sites for antigens - specific for certain antigens - hold and present a processed antigen on the surface of the cell membrane - bind to antigen receptor on B or T cells and stimulate response Cytokines: Copyright © McGraw-Hill Education. Permission required for reproduction or display. - proteins secreted by a cell that regulates neighboring cells - Ex. Interleukin 1 released by macrophages stimulates helper T cells Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Lymphocyte Proliferation 1. After antigen is processed and present to helper T cells, helper T cell produces interleukin-2 and interleukin 2-receptors 2. Interleukin-2 binds to receptors and stimulates more helper T cells production 3. Helper T cells are needed to produce B cells 4. B cells produce antibodies Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Dual Nature of Immune System Lymphocytes give rise to 2 types of immune responses: antibody-mediated and cell- mediated Antigens can trigger both types of responses Both types are able to recognize self vs. nonself, use specificity, and have memory Antibody-Mediated 59 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  What is it? - effective against antigens in body fluids (blood and lymph) - effective against bacteria, viruses, toxins - uses B cells to produce antibodies Antibody Structure Letter Y shape Variable region: - V of Y - bind to epitopes of antigen using antigen binding site 60 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Constant region: - stem of Y - each class of immunoglobulin has same structure 61 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Figure 14.12 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Antigen-binding site: site on antibody where antigen binds Valence: number of antigen-binding sites on antibody 5 immunoglobulins used to destroy antigens: IgG, IgM, IgA, IgE, IgD 68 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Effects of Antibodies Inactivate antigen Bind antigens together Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Active complement cascades Initiate release of inflammatory chemicals Facilitate phagocytosis Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Figure 14.13 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Antibody Production Primary response 1st exposure of B cell to antigen B cell undergoes division and forms plasma cell and memory cells Plasma cells: - produce antibodies - 3-14 days to by effective against antigen - person develop disease symptoms Secondary Response Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Memory cells: - occurs when immune system is exposed to antigen that has been seen before - B memory cells quickly divided to form plasma cells which produce antibodies - produces new memory cells Copyright © McGraw-Hill Education. Permission required for reproduction or display. Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Cell-Mediated Immunity What is it? - effective against antigens in cells and tissues - effective against bacteria, viruses, fungi, and protozoa - uses different types of T cells 70 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Types of T cells Helper T cells (TH): - activate macrophages - help form B cells - promote production of Tc Cytotoxic T cells (Tc): precursor to cytotoxic T lymphocytes (CTL) 71 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Cytotoxic T lymphocytes (CTL): destroys antigen on contact Regulatory T cells (Tr): turn off immune system response when antigen is gone 72 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Figure 14.16 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Figure 14.17 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Types of Adaptive Immunity Naturally Acquired Immunity Active: - natural exposure to antigens causes production of antibodies - can be lifelong immunity - Ex. Mononucleosis Passive: - transfer of antibodies from mother to child - Ex. Breast milk or placenta 80 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Artificially Acquired Immunity Active: - injection of antigens using vaccines which cause the production of antibodies - vaccine or immunization: process of introducing killed, live, or inactivated pathogen Passive: injection of antibodies from another person or animal 81 Copyright © McGraw-Hill Education. Permission required for reproduction or display.  Figure 14.18 Copyright © McGraw-Hill Education. Permission required for reproduction or display.