Immune System Madeleine Myers RN, MS, FNP

Objectives List three functions of the lymphatic system. Describe the composition and flow of lymph. State the location of the following lymph nodes: cervical nodes, axillary nodes, and inguinal nodes. Describe the four lymphoid organs: lymph nodes, tonsils, thymus gland, and spleen List three functions of the lymphatic system. Describe the composition and flow of lymph. State the location of the following lymph nodes: cervical nodes, axillary nodes, and inguinal nodes. Describe the four lymphoid organs: lymph nodes, tonsils, thymus gland, and spleen

The Lymphatic System Main functions: –Return tissue fluid to the blood –Intestinal absorption of fats and fat-soluble vitamins –Helps the body defend itself against disease

Functions of the Immune System To protect the entire body from a variety of harmful substances –pathogenic microorganisms –allergens –toxins –malignant cells

The Lymphatic System Elephantiasis

Plasma plasma –92% water –8% plasma proteins albumin globulin fibrinogen serum - plasma without clotting proteins or fibrinogen

The Lymphatic System (cont’d.) Lymph: clear fluid that resembles plasma and is formed from plasma during capillary exchange Composition of lymph: water, electrolytes, waste from metabolizing cells, and some protein that leaks out of the capillaries of the systemic circulation

Structures of the Immune System Unlike other body systems, Immune System is NOT contained within a single set of organs or vessels Action depends on structures from lymphatic, cardiovascular, and Integumentary systems Works primarily through antigen-antibody reaction

Lymphatic System Major structures –lymph vessels –lymph nodes –lymph fluid –tonsils Also –spleen –thymus

The Lymphatic System

Lymph System Lymph originates in blood plasma Interstitial fluid cleans and nourishes body tissues collects cellular debris, bacteria return to blood or lymph capillaries

Lymph Nodes located in lymph vessels small round or oval structures (filters) depositories for cellular debris bacteria and debris phagocytized

Lymph Nodes inside are masses of tissue which contain WBCs (lymphocytes) almost always grouped 2 or 3 to 100 invading cells destroyed in nodes and often swell as an indicator of the disease process

Spleen sac-like mass of lymphatic tissue filter for lymph phagocytic cells hemolytic

Thymus lymphatic tissue mediastinum primary role: changes lymphocytes to T cells for cellular immunity

Tonsils masses of lymph tissue designed to filter tissue fluid, not lymph located beneath certain areas of moist epithelium exposed to outside and hence to contamination any or all may become so loaded with bacteria that the pathogens gain dominance should not be removed unless absolutely necessary.

Antigen-Antibody Reactions Antigen - any substance that the body regards as foreign (virus, bacterium, toxin) Antibody - a disease fighting protein developed by the body in response to the presence of an antigen Antigen-antibody reaction or immune reaction

Web pages Inflamatory response ontent/inflammatory.htmlhttp:// ontent/inflammatory.html HIV ecyclehiv.htmlhttp:// ecyclehiv.html aninmations Movie mlhttp:// ml

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Functions of the Lymph System lymph/o drain fluid from tissue spaces and return to it to the blood transport materials (nutrients, hormones and oxygen) to body cells carry away waste products to the blood transport lipids away from digestive system control of infection

Lymphoid Organs

The Lymphatic System Lymph capillaries and blood capillaries.

The Lymphatic System (cont’d.) Lymphatic vessels: includes lymphatic capillaries and several larger lymphatic vessels; “run with” the veins

Lymphoid Organs Organs: –Lymph nodes –Tonsils –Thymus gland –Spleen Functions: –Filter particles from lymph, tissue fluid, and blood –Support activities of lymphocytes Organs: –Lymph nodes –Tonsils –Thymus gland –Spleen Functions: –Filter particles from lymph, tissue fluid, and blood –Support activities of lymphocytes

Immune System

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 26 Lesson 21.1 Objectives Differentiate between specific and nonspecific immunity. Describe the process of phagocytosis. Explain the causes of the signs of inflammation. Explain the role of fever in fighting infection. Explain the role of T cells in cell-mediated immunity.

Lesson 21.1 Objectives (cont’d.) Explain the role of B cells in antibody- mediated immunity. Differentiate between genetic immunity and acquired immunity. Describe naturally and artificially acquired active and passive immunity. Identify the steps in the development of anaphylaxis.

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. Classification of the Immune System Immunology: study of the immune system Immunity: elaborate defense system of the human body –Nonspecific immunity: protects the body against many different types of foreign agents –Specific immunity: hones in on a foreign substance and provides protection against one specific substance but no others

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 29 Classification of the Immune System (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 30 Classification of the Immune System (cont’d.) Nonspecific immunity: –First line of defense –Second line of defense Specific immunity: –Third line of defense

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 31 Nonspecific Immunity First line of defense: –Mechanical barriers –Chemical barriers –Certain reflexes

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 32 Nonspecific Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 33 Second line of defense –Phagocytosis –Inflammation –Fever –Protective proteins –Natural killer cells Nonspecific Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 34 Phagocytosis: –Phagocyte’s plasma membrane sends out pseudopods to surround pathogen –Pathogen is captured when pseudopods fuse –Lysosomal membrane fuses with pathogen –Potent enzymes are released to destroy pathogen Nonspecific Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 35 Inflammation: responses the body makes when confronted by an irritant –Signs of inflammation: redness, heat, swelling, pain –Infection: inflammation caused by pathogenic irritant –Histamine: released by cells when tissues are injured or irritated –Pus: thick, yellowish accumulation of dead leukocytes, pathogens, injured cells, and tissue fluid Nonspecific Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 36 Fever: abnormal elevation in body temperature –Pyrogens: fever-producing substances released by phagocytes; stimulate the hypothalamus to reset the body’s temperature and produce a fever Nonspecific Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 37 Protective proteins: –Interferons: group of proteins secreted by cells infected by a virus –Complement proteins: attach to outer membrane of bacterium to fill it with fluid and electrolytes, causing lysis; enhance phagocytosis and inflammatory response Natural killer (NK) cells: special types of lymphocytes that act nonspecifically to kill various cells Nonspecific Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 38 Third line of defense: –Lymphocytes T lymphocytes B lymphocytes –Macrophages Antigen: substance that stimulates the formation of antibodies Specific Immunity

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 39 Specific Immunity (cont’d.) Lymphocytes: –T lymphocytes (T cells): Thymus-derived lymphocytes Live and work in lymphoid tissue and circulate in blood Comprise 70% to 80% of the blood’s lymphocytes Attack antigens directly through cell-to-cell contact, or cell-mediated immunity

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 40 Specific Immunity (cont’d.) Cell- mediated immunity.

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 41 T cells: cell-mediated immunity –Killer T cells: punch holes in pathogen’s cell membrane and secrete lymphokines that enhance phagocytic activity –Helper T cells: secrete a lymphokine that stimulates T cells and B cells and enhances immune response –Suppressor T cells: inhibit immune response when the antigen has been destroyed –Memory T cells: remember the initial encounter with an antigen and quickly reproduce and allow a faster immune response in subsequent encounters Specific Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 42 Lymphocytes: –B lymphocytes (B cells): Liver and bone marrow-derived lymphocytes Live and work in lymphoid tissue and circulate in blood Comprise 20% to 30% of the blood’s lymphocytes Interact with antigens indirectly through the secretion of antibodies, or antibody-mediated immunity Specific Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 43 Specific Immunity (cont’d.) Antibody- mediated immunity.

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 44 B cells: antibody-mediated immunity –Immunoglobulins: antibodies secreted by B cells found in the gamma globulin part of plasma proteins –Three most abundant types of immunoglobulin: Immunoglobulin G (IgG) Immunoglobulin A (IgA) Immunoglobulin M (IgM) Specific Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 45 Antigen-antibody reaction: antibodies bind to antigens and react with antigens directly Agglutination: the clumping together of the antigen-antibody components Activated complement proteins: stimulate chemotaxis, promote agglutination, make pathogens more susceptible to phagocytosis, and encourage lysis Specific Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 46 Specific Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 47 Types of Immunity Two main categories of immunity: –Genetic immunity: genetic information conveys immunity to certain diseases –Acquired immunity: received during person’s lifetime, either naturally or artificially

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 48 Types of Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 49 Acquired Immunity Naturally acquired immunity –Active immunity: antibodies and memory cells are produced in the body after first exposure to a specific pathogen –Passive immunity: antibodies that were developed in response to the pathogens the mother encountered in her life are passed to a fetus by the mother

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 50 Artificially acquired immunity –Active immunity: Vaccine: antigen-bearing substance injected into a person to stimulate antibody production –Passive immunity: Immune globulin: obtained from a donor that has developed the antibodies in response to a specific antigen Acquired Immunity (cont’d.)

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 51 Other Immunologic Responses Allergic reactions: immune system forms antibodies to substances not usually recognized as foreign –Delayed-reaction allergy –Immediate hypersensitivity reaction

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 52 Other Immunologic Responses (cont’d.) Immediate reaction allergy.

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 53 Other Immunologic Responses (cont’d.) Autoimmune diseases: develop in response to self attack, or autoimmunity Organ rejection: recipient’s immune system recognizes donated organ as foreign and mounts an immune attack against it

Review

WBCs for Immune Reactions monocytes - type of lymphocytes –formed in bone marrow/transported where needed by body –become macrophages macrophage - phagocytic cell that protects body by ingesting invading cells lymphocytes - major class of WBCs –formed in lymphatic tissue

Lymphocytes T cells or T Lymphocytes –mature in thymus gland –Cell mediated immunity B cells or B Lymphocytes –mature in bone marrow –antibody-mediated immunity

T Cell or T Lymphocyte (Cell Mediated Immunity) T Cell (cell mediated immunity) –circulating lymphocytes –produced in bone marrow –matures in thymus –live for years –primary function: coordinate immune defenses and kill organisms

Lymphocyte: T Cells helper T cells - essential to proper functioning of immune system Memory cells- remember antigens and stimulate a faster response if same antigen introduced at a later time

Immunity Immunity-state of being resistant or not susceptible to a specific disease Acquired immunity-any form of immunity NOT present at birth and obtained during life

Factors That Influence Immune System Health Age Heredity

Acquired Immune Deficiency Syndrome (AIDS) Caused by HIV (Human Immunodeficiency Virus) HIV infects T-helper cells with often a long incubation of up to 10 years AIDS name applied during advanced stages of disease After immune system destroyed, opportunistic infections occur.

Autoimmune Disorders Antigens stimulate development of antibodies that are unable to distinguish antigens of internal cells. Body makes antibodies and T cells against itself and attacks own tissues. Multisystemic involvement. Myasthenia gravis, rheumatoid arthritis

Infectious Mononucleosis Acute infection caused by virus. Fever, sore throat, swollen lymph glands, atypical lymphocytes, splenomegaly, hepatomegaly, abnormal liver function, and bruising. transmitted by droplet infection Infection confers permanent immunity Treatment symptomatic

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