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The Body Defenses. Body Defense Overview Innate Immunity –Barrier Defenses –Internal Defenses Acquired Immunity –Humoral Response –Cell-mediated Response.

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Presentation on theme: "The Body Defenses. Body Defense Overview Innate Immunity –Barrier Defenses –Internal Defenses Acquired Immunity –Humoral Response –Cell-mediated Response."— Presentation transcript:

1 The Body Defenses

2 Body Defense Overview Innate Immunity –Barrier Defenses –Internal Defenses Acquired Immunity –Humoral Response –Cell-mediated Response

3 Innate Immunity in Invertebrates (Nonspecific) Chitin (physical barrier) in intestine Lysozymes and low pH (digests microbial cell walls) Hemocytes in hemolymph –Phagocytosis –Antimicrobial peptides

4 Innate Immunity in Vertebrates Barrier Defenses (Nonspecific) Skin –Physical Barrier & Lysozymes Digestive Tract –High acidity & normal bacteria Respiratory Tract –Mucus & Cilia Genitourinary Tract –Acidity of Urine

5 Innate Immunity in Vertebrates Internal Defenses (Nonspecific) Phagocytic White Blood Cells The Inflammatory Response Antimicrobial Proteins Natural Killer Cells

6 Phagocytic White Blood Cells (Leukocytes) Neutrophils (70%) –short lived Monocytes (5%) –macrophages –long lived in lymphatic tissue Eosinophils (1.5%) –attack larger parasites

7 The Inflammatory Response Releases histamine –(basophils and mast cells) Allows for dilation and increased permeability Increased temp due to increased blood flow Cytokines (protein) direct migration of Phagocytes (activate lymphocytes)

8 Antimicrobial Proteins Compliment System –30 proteins –lyses viruses and pathogens –may attract phagocytes and cause adherence –Two pathways Alternative –triggered by substances on invaders and does not use antibodies Classical –triggered by antigens and uses antibodies

9 Antimicrobial Proteins Interferon –proteins secreted by viral infected cells –diffuse to surrounding cells –surrounding cells make chemicals that inhibit viral reproduction

10 Natural Killer Cells Recognize damaged or diseased cells –Class 1 MHC molecule on surface of most cells –Missing when diseased Release chemical to destroy cells lacking this protein

11 Acquired Immunity Vertebrates –Uses Lymphocytes to recognize antigens –Two major types B lymphocytes T lymphocytes

12 The Development of Lymphocytes B cells –made and mature in bone marrow T cells –made in bone marrow and matures in thymus

13 Epitopes Antigenic determinant (special areas on antigens –Usually has several


15 Antigen Recognition by Lymphocytes B Cells – Y shaped receptors made up of 4 polypeptide chains (two heavy / two light) Recognize intact antigens

16 Antigen Recognition by Lymphocytes T Cells – 2 polypeptide chains (an alpha chain and a beta chain) Recognize small fragments of antigens

17 Major Histocompatibility Complex Class 1 MHC molecules –Work with Cytotoxic T cells Class 2 MHC molecules –Work with both Cytotoxic T Cells Helper T cells


19 Immune Response Primary Immune Response –Takes 10 - 17 days from initial exposure to an antigen –Produces B and T cells Secondary Immune Response –takes 2 - 7 days from re-exposure to antigen


21 Immune Responses Humoral Immunity –involves B cells –produces antibodies that circulate in the blood, plasma and lymph –cells do not have to be next to antigen to attack Cell-mediated Immunity –involves T cells –cells must be next to antigens to attack

22 Response to Nearly All Antigens Helper T cells –attach to macrophage that has attacked an antigen often uses CD4 receptors –releases interleukin (Cytokine) –activates Cytotoxic T cells and Plasma B cells

23 Cell-mediated Response Cytotoxic T cells –attach to infected cells / Cancer Cells –Usually uses a CD8 receptor –perforin (protein) makes a pore in membrane –ions and water enters pores –infected cell lyses

24 B Cells: A Response to Extracellular Pathogens –Response to extracellular pathogens –Plasma B cells produce antibodies –Memory B cells live a long time and can help produce other B cells quickly when re-infected by the same antigen

25 Antibodies A group of globular serum proteins called immunoglobulins

26 Immunity in Health and Disease Active Immunity –Getting the disease –Immunizations (Vaccinations) Passive Immunity –Antibodies transferred from one individual to another pregnancy and breast feeding injection of antibodies

27 Abnormal Immune Function Allergies –hypersensitive responses to antigens –anaphylactic shock Autoimmune Diseases –immune system attacks own body Lupus, MS, ALS, Rheumatoid Arthritis Immunodeficiency Diseases –lowered immune system –SCIDS, AIDS

28 Stages of HIV Infect- ions

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