What is the difference between nonspecific and specific defense, and the role of lymphocytes in the immune response?

????????? The ability to resist infection and disease

Immunity The ability to resist infection and disease

?????????? Defenses Lymphocytes: part of the immune response Identify, attack, and develop immunity: to a specific pathogen

Specific Defenses Lymphocytes: Identify, attack, and develop immunity: part of the immune response Identify, attack, and develop immunity: to a specific pathogen

Nonspecific Defenses Block or attack any potential infectious organism Cannot distinguish one attack from another PLAY Immunity: Nonspecific Defenses

What are the major components of the lymphatic system and their functions?

4 Parts of the Lymphatic System What are they?

4 Parts of the Lymphatic System a fluid similar to plasma does not have plasma proteins Lymphatic vessels (lymphatics): network that carries lymph from peripheral tissues to the venous system

4 Parts of the Lymphatic System Lymphoid tissues and lymphoid organs: found throughout the body Lymphocytes, phagocytes, and other immune system cells

Organization of the Lymphatic System PLAY 3D Rotation of the Lymphatic System Figure 22–1

Lymphocyte Production 3 places that lymphocytes are produced:

Lymphocyte Production Lymphocytes are produced: lymphoid organs (e.g., spleen, thymus) and in red bone marrow in lymphoid tissues (e.g., tonsils)

Lymphocyte Distribution Lymphocytes: detect problems travel into site of injury or infection

???????? Are special lymphatic capillaries in small intestine Transport lipids from digestive tract

Lacteals Are special lymphatic capillaries in small intestine Transport lipids from digestive tract

Lymphatic Vessels and Valves Figure 22–3

?????????????? Blockage of lymph drainage from a limb Causes severe swelling Interferes with immune system function

Lymphedema Blockage of lymph drainage from a limb Causes severe swelling Interferes with immune system function

Why are lymphocytes important, and how are they distributed in the body?

Lymphocytes Make up ????????????? % of circulating leukocytes Most are stored, not circulating

Lymphocytes Make up 20–30% of circulating leukocytes Most are stored, not circulating

3 Classes of Circulating Lymphocytes

3 Classes of Circulating Lymphocytes T cells: thymus-dependent Make up 80% of circulating lymphocytes B cells: bone–marrow derived NK cells: natural killer cells

3 Main Types of T Cells

3 Main Types of T Cells Cytotoxic T cells Helper T cells Suppressor T cells

Cytotoxic T Cells Attack cells infected by viruses Produce cell-mediated immunity

Helper T Cells Stimulate function of T cells and B cells

Suppressor T Cells Inhibit function of T cells and B cells

“Regulatory T Cells” Are helper and suppressor T cells Control sensitivity of immune response

B Cells Make up 10–15% of circulating lymphocytes Differentiate into ??????????????? cells

B Cells Make up 10–15% of circulating lymphocytes Differentiate into plasma cells

Plasma Cells Produce and secrete ???????????? (immunoglobin proteins)

Plasma Cells Produce and secrete antibodies (immunoglobin proteins)

???????????? Targets which identify any pathogen or foreign compound

Antigens Targets which identify any pathogen or foreign compound

Natural Killer (NK) Cells Also called large granular lymphocytes Make up 5–10% of circulating lymphocytes

Natural Killer (NK) Cells Responsible for immunological surveillance Attack: foreign cells virus-infected cells cancer cells

Production and Distribution of Lymphocytes Figure 22–5

Lymphoid Stem Cells Group 1: remain in bone marrow produce B cells and natural killer cells

Lymphoid Stem Cells Group 2: migrate to thymus produce T cells in environment isolated by blood-thymus barrier

T Cells and B Cells Migrate throughout the body: to defend peripheral tissues Retain their ability to divide: is essential to immune system function

What are the structures and functions of lymphoid tissues and organs?

Lymphoid Tissues Connective tissues dominated by lymphocytes

Lymphoid Nodules Figure 22–6

Lymphoid Nodule Areolar tissue with densely packed lymphocytes Germinal center contains dividing lymphocytes

Distribution of Lymphoid Nodules Lymph nodes Spleen Respiratory tract (tonsils) Along digestive and urinary tracts

Mucosa-Associated Lymphoid Tissue (???????????????) Lymphoid tissues associated with the digestive system: aggregated lymphoid nodules: clustered deep to intestinal epithelial lining Appendix: mass of fused lymphoid nodules

Mucosa-Associated Lymphoid Tissue (MALT) Lymphoid tissues associated with the digestive system: aggregated lymphoid nodules: clustered deep to intestinal epithelial lining Appendix: mass of fused lymphoid nodules

The 5 ?????????? In wall of pharynx: left and right palatine ?? pharyngeal ? (adenoid) 2 lingual ??

The 5 Tonsils In wall of pharynx: left and right palatine tonsils pharyngeal tonsil (adenoid) 2 lingual tonsils

Lymphoid Organs Are separated from surrounding tissues By a fibrous connective-tissue capsule Lymph nodes Thymus Spleen

Lymph Nodes Range from 1–25 mm diameter Figure 22–7

?????????????? Chronic or excessive enlargement of lymph nodes may indicate infections, endocrine disorders, or cancer

Lymphadenopathy Chronic or excessive enlargement of lymph nodes may indicate infections, endocrine disorders, or cancer

Antigen ????????????? First step in immune response Extracted antigens are “presented” to lymphocytes: or attached to dendritic cells to stimulate lymphocytes

Antigen Presentation First step in immune response Extracted antigens are “presented” to lymphocytes: or attached to dendritic cells to stimulate lymphocytes

The ?????????????? Located in mediastinum Deteriorates after puberty: diminishing effectiveness of immune system

The Thymus Located in mediastinum Deteriorates after puberty: diminishing effectiveness of immune system

The Thymus Figure 22–8

Thymus Hormones ?????????????? Promote development of lymphocytes

Thymus Hormones Thymosins Promote development of lymphocytes

3 Functions of the Spleen Figure 22–9

3 Functions of the Spleen Removal of abnormal blood cells and other blood components by phagocytosis Storage of iron recycled from red blood cells

3 Functions of the Spleen Initiation of immune responses by B cells and T cells: in response to antigens in circulating blood

What are the body’s nonspecific defenses and their functions?

SEVEN Nonspecific Defenses Always work the same way Against any type of invading agent ???????

7 Types of Nonspecific Resistance Physical barriers Phagocytic cells Immunological surveillance Interferons Complement Inflammation Fever

The 7 Nonspecific Defenses Figure 22–10

Complement (C) Proteins Form the complement system Complements action of antibodies PLAY Immunity: Complement

What is specific resistance What is specific resistance? What are the forms and properties of immunity?

Forms of Immunity Figure 22–14

Forms of Immunity ?????????: present at birth after birth

Forms of Immunity Innate: present at birth Acquired after birth

Acquired Immunity ????????: antibodies develop after exposure to antigen antibodies are transferred from another source

Acquired Immunity Active: Passive: antibodies develop after exposure to antigen Passive: antibodies are transferred from another source

Active Immunity ??????????? ?????????: through environmental exposure to pathogens ????????????: through vaccines containing pathogens

Active Immunity Naturally acquired: Induced: through environmental exposure to pathogens Induced: through vaccines containing pathogens

Passive Immunity Naturally acquired: Induced: antibodies acquired from the mother Induced: by an injection of antibodies

What are the differences between cell-mediated (cellular) immunity and antibody-mediated (humoral) immunity?

The Immune Response Figure 22–15 (Navigator)

The Immune Response 2 main divisions: cell mediated immunity (??????? cells) antibody mediated immunity (?????? cells) PLAY Immunity: Cell-Mediated Immunity

The Immune Response 2 main divisions: cell mediated immunity (T cells) antibody mediated immunity (B cells) PLAY Immunity: Cell-Mediated Immunity

What are the types of T cells and their functions in the immune response?

Antigens and MHC Proteins PLAY Antigens and MHC Proteins Figure 22–16a (Navigator)

2 Classes of MHC Proteins found in membranes of all nucleated cells found in membranes of antigen-presenting cells (APCs) found in lymphocytes

2 Classes of MHC Proteins Class I: found in membranes of all nucleated cells Class II: found in membranes of antigen-presenting cells (APCs) found in lymphocytes

??????????? Cells (APCs) Responsible for activating T cells against foreign cells and proteins

Antigen-Presenting Cells (APCs) Responsible for activating T cells against foreign cells and proteins

Phagocytic APCs Free and fixed macrophages: Kupffer cells: Microglia: in connective tissues Kupffer cells: of the liver Microglia: in the CNS

Pinocytic APCs Langerhans cells: Dendritic cells: in the skin in lymph nodes and spleen

Actions of ??????????? T Cells Release perforin: to destroy antigenic cell membrane Secrete poisonous lymphotoxin: to destroy target cell Activate genes in target cell: that cause cell to die

Actions of Cytotoxic T Cells Release perforin: to destroy antigenic cell membrane Secrete poisonous lymphotoxin: to destroy target cell Activate genes in target cell: that cause cell to die

4 Functions of ?????????? Stimulate T cell divisions: produce memory T cells accelerate cytotoxic T cell maturation Attract and stimulate macrophages Attract and stimulate NK cells Promote activation of B cells

4 Functions of Cytokines Stimulate T cell divisions: produce memory T cells accelerate cytotoxic T cell maturation Attract and stimulate macrophages Attract and stimulate NK cells Promote activation of B cells

??????????? Cells Responsible for antibody-mediated immunity Attack antigens by producing specific antibodies Millions of populations, each with different antibody molecules PLAY Immunity: Antibody-Mediated Immunity

B Cells Responsible for antibody-mediated immunity Attack antigens by producing specific antibodies Millions of populations, each with different antibody molecules PLAY Immunity: Antibody-Mediated Immunity

B Cell ????????????? Corresponding antigens in interstitial fluids bind to B cell receptors B cell prepares for activation Preparation process is sensitization

B Cell Sensitization Corresponding antigens in interstitial fluids bind to B cell receptors B cell prepares for activation Preparation process is sensitization

B Cell Sensitization and Activation PLAY B Cell Sensitization and Activation Figure 22–20 (Navigator)

B Cell Sensitization During sensitization, antigens are: taken into the B cell processed reappear on surface, bound to Class II MHC protein

What is the structure of an antibody, and what types of antibodies are found in body fluids and secretions?

Antibody Structure Figure 22–21a, b

Antibody Structure 2 parallel pairs of polypeptide chains: 1 pair of heavy chains 1 pair of light chains Each chain contains: constant segments variable segments

5 Heavy-Chain Constant Segments Determine 5 types of antibodies: ??????????????????????

5 Heavy-Chain Constant Segments Determine 5 types of antibodies: IgG IgE IgD IgM IgA

Antibody Function Figure 22–21c, d

A ???????????? Also called partial antigen Must attach to a carrier molecule to act as a complete antigen

A Hapten Also called partial antigen Must attach to a carrier molecule to act as a complete antigen

Dangers of Haptens Antibodies produced attack both hapten and carrier molecule If carrier is “normal”: antibody attacks normal cells e.g., penicillin allergy

What are the functions of antibodies and how are they performed?

7 Functions of Antigen–Antibody Complexes

7 Functions of Antigen–Antibody Complexes Neutralization of antigen binding sites Precipitation and agglutination: formation of immune complex

7 Functions of Antigen–Antibody Complexes Activation of complement Attraction of phagocytes Opsonization: increasing phagocyte efficiency

7 Functions of Antigen–Antibody Complexes Stimulation of inflammation Prevention of bacterial and viral adhesion

What are the primary and secondary responses to antigen exposure?

Primary and Secondary Responses Occur in both cell-mediated and antibody-mediated immunity Figure 22–22

The Primary Response Peak response: IgM: can take 2 weeks to develop declines rapidly IgM: is produced faster than IgG is less effective

The Secondary Response Activates memory B cells: at lower antigen concentrations than original B cells secrete antibodies in massive qualities

Body Responses to Bacterial Infection Figure 22–24

Combined Immune System Responses Figure 22–25

Hormones of the Immune System Table 22–3

???????????? Disorders A malfunction of system that recognizes and ignores “normal” antigens Activated B cells make autoantibodies against body cells

Autoimmune Disorders A malfunction of system that recognizes and ignores “normal” antigens Activated B cells make autoantibodies against body cells

Autoimmune Disorders Thyroiditis Rheumatoid arthritis Insulin-dependent diabetes mellitus

Immunodeficiency Diseases 3 examples (categories):

Immunodeficiency Diseases Problems with embryological development of lymphoid tissues: can result in severe combined immunodeficiency disease (SCID)

Immunodeficiency Diseases Viral infections such as HIV: can result in AIDS

Immunodeficiency Diseases Immunosuppressive drugs or radiation treatments: can lead to complete immunological failure

?????????????? Inappropriate or excessive immune responses to antigens Allergens: antigens that trigger allergic reactions

Allergies Inappropriate or excessive immune responses to antigens Allergens: antigens that trigger allergic reactions

4 Categories of Allergic Reactions ????

4 Categories of Allergic Reactions Type I: immediate hypersensitivity Type II: cytotoxic reactions

4 Categories of Allergic Reactions Type III: immune complex disorders Type IV: delayed hypersensitivity

Type I Allergy (1 of 3) Also called immediate hypersensitivity A rapid and severe response to the presence of an antigen Most commonly recognized type of allergy Includes allergic rhinitis (environmental allergies)

Type I Allergy (2 of 3) Sensitization leads to: production of large quantities of IgE antibodies distributed throughout the body Second exposure leads to: massive inflammation of affected tissues

Type I Allergy (3 of 3) Severity of reaction depends on: individual sensitivity locations involved Allergens in blood stream may cause anaphylaxis

Anaphylaxis (1 of 2) Can be fatal Affects cells throughout body Changes capillary permeability: produce swelling (hives) on skin

Anaphylaxis (2 of 2) Smooth muscles of respiratory system contract: make breathing difficult Peripheral vasodilatation: can cause circulatory collapse (anaphylactic shock)

What are the effects of stress on immune function?

Stress and the Immune Response ???????????????????: secreted to limit immune response long-term secretion (chronic stress): inhibits immune response lowers resistance to disease

Stress and the Immune Response Glucocorticoids: secreted to limit immune response long-term secretion (chronic stress): inhibits immune response lowers resistance to disease

Functions of Glucocorticoids Depression of the inflammatory response Reduction in abundance and activity of phagocytes Inhibition of interleukin secretion