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76 Cards in this Set
- Front
- Back
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a surface protection composed of anatomical and physiological barriers that keep microbes from penetrating sterile body compartments; include: physical barriers, chemical barriers, and genetic composition; innate/nonspecific immunity
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first line of defense
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a cellular and chemical system that comes immediately into play if infectious agents make it past the surface defenses; examples include phagocytes that engulf foreign matter and destroy it, and inflammation that holds infection in check; includes: inflammatory response, interferons, phagocytosis, and complement; innate/nonspecific immunity
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second line of defence
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includes specific host defenses that must be developed uniquely for each microbe through the action of specialized white blood cells; this form of immunity is usually long term and has memory; includes: antibodies, B cells, T cells, accessory cells, and cytokines; acquired/specific immunity
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third line of defense
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barriers at the portal of entry: a first line of defense
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-glands
-urination -defecation -sweating -intact skin -wax -mucous -saliva -tears -low pH -stomach acid -intestine enzymes -cilia |
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tears, saliva, and mucous are
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lysozymes
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-sebaceous secretions and specialized glands
-lysozymes in tears -lactic acid and electrolyte concentrations of sweat -skin's acidic pH and fatty acid content -HCl in stomach -digestive juices and bile in intestine -semen -acidic pH in the vagina |
nonspecific chemical defenses
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some hosts are genetically immune to the diseases of other others and this is particularly true of these; lock and key fit
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viruses
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specifically active on peptidoglycan on cell walls of gram positive
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lysozymes
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2 antimicrobial chemicals of nonspecific defense
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sebaceous secretions and specialized glands, and semen
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the study of all features of the body's second and third lines of defense
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immunology
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healthy functioning immune system is responsible for:
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1. surveillance of body
2. recognition of foreign material 3. destruciton of entities deemed to be foreign |
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white blood cells must distinguish between _____ and _____
they evaluate these cells by examining ____ on their surfaces (proteins expressed on the surface of a cell) |
self, non self
markers |
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Body compartments involved in immune defenses
• Physically separated but have numerous connections |
- Intracellular
– Extracellular – Lymphatic – Cerebrospinal – Circulatory |
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body compartments that participate in immune function
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• Reticuloendothelial system (RES)
• Spaces containing extracellular fluid (ECF) • Bloodstream • Lymphatic system |
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• Provides a passageway within and between
tissues and organs • Coexists with the mononuclear phagocyte system |
Reticuloendothelial system
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cells involved in RES
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-macrophages
-dendritic cells -neutrophils |
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the origin of the blood
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circulatory system
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2 parts of the circulatory system
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1. circulatory system proper
2. lymphatic system |
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unclotted whole blood (top to bottom)
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-plasma
-buffy coat -red blood cells |
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clotted whole blood (top to bottom)
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-serum
-clot |
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• Hundreds of different chemicals
• Main component is water (92%) • Proteins such as albumin and globulins, immunochemicals, fibrinogen and other clotting factors, hormones, nutrients, dissolved gases, and waste products |
plasma
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production of blood cells
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Hematopoesis
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Relatively short life
• Primary precursor of new blood cells: pluripotential stem cells in the marrow – Red blood cells (erythrocytes) – White blood cells (leukocytes) – Platelets (thrombocytes) • Differentiation |
blood cells
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in adults stem cells produced in
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bone marrow
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2 types of leukocytes
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1. granulocytes
2. agranulocytes |
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3 types of granulocytes
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1. neutrophils
2. eosinophils 3. basophils |
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phagocytosis
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neutrophils
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– Attack and destroy large eukaryotic pathogens
– Also involved in inflammation and allergic reactions |
eosinophils
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– Parallel eosinophils in many actions
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basophils
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2 types of agranulocytosis
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1. monocytes
2. lymphocytes |
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• Discharged by bone marrow into bloodstream, live as
phagocytes for a few days, then differentiate into macrophages • Responsible for – Many specific and nonspecific phagocytic and killing functions – Processing foreign molecules and presenting them to lymphocytes – Secreting biologically active compounds that assist, mediate, attract, and inhibit immune cells and reactions • Dendritic cells |
monocytes
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• Key cells in the third line of defense and the specific
immune response • When stimulated by antigens, transform into activated cells that neutralize and destroy that foreign substance |
lymphocytes
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Humoral immunity; Produce specialized plasma cells which produce antibodies
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B cells
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Cell-mediated immunity
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T cells
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T cells modulate immune
functions and kill foreign cells |
Cell-mediated immunity
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protective molecules carried in the
fluids of the body |
Humoral immunity
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– Develop from stem cells in the bone marrow
– Lose their nucleus just prior to entering circulation – Transport oxygen and carbon dioxide to and from the tissues |
erythrocytes
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– Formed elements in circulating blood
– Not whole cells – Function primarily in hemostasis and in releasing chemicals for blood clotting and inflammation |
platelets
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compartmentalized network
of vessels, cells, and specialized accessory organs • Transports lymph through a system of vessels and lymph nodes • Major functions – Provide an auxiliary route for the return of extracellular fluid to the circulatory system proper – Act as a drain-off system for the inflammatory response – Render surveillance, recognition, and protection against foreign materials |
Lymphatic system:
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Plasma-like liquid formed when certain blood
components move out of blood vessels into the extracellular spaces and diffuse or migrate into the lymphatic capillaries • Composition parallels that of plasma, but without red blood cells |
lymphatic fluid
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• Along the lines of blood vessels
• Similar to thin-walled veins • High numbers in hands, feet, and around the areola of the breast • Flow of lymph is in one direction only- from extremities toward the heart • Lymph is moved through the contraction of skeletal muscles through which the lymphatic ducts wend their way |
lymphatic vessels
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lymphoid organs and tissues
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• Lymph nodes
• Thymus • Spleen • Gut-associated lymphoid tissue (GALT) • Tonsils • Loose connective tissue framework that houses aggregations of lymphocytes |
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• Small, encapsulated, bean-shaped organs
• Usually found in clusters along lymphatic channels and large blood vessels of the thoracic and abdominal cavities • Major aggregations: axillary nodes, inguinal nodes, cervical nodes |
lymph nodes
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• Similar to a lymph node except it filters blood
instead of lymph • Filters pathogens from the blood |
spleen
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site of T cell maturation; originates in the embryo
• High rates of activity and growth until puberty • Shrinks gradually through adulthood • Thymic hormones help thymocytes develop specificity to be released as mature T cells |
thymus
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• Bundles lie at many sites on or just
beneath the mucosa of the gastrointestinal and respiratory tracts • Tonsils • Breasts of pregnant and lactating women • GALT in the intestinal tract – Appendix – Lacteals – Peyer’s patches • Mucosal-associated lymphoid tissue (MALT) • Skin-associated lymphoid tissue (SALT) • Bronchial-associated lymphoid tissue (BALT) |
lymphocytes
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the second line of defense
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• Inflammation
• Phagocytosis • Interferon • Complement |
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a complex concert of reaction to injury
• Reaction to any traumatic event in the tissues • Classic signs and symptoms – Rubor (redness) – Calor (warmth) – Tumor (swelling) – Dolor (pain) • Fifth symptom has been added: loss of function |
inflammatory response
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• Chief functions of inflammation
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– Mobilize and attract immune components to the
site of the injury – Set in motion mechanisms to repair tissue damage and localize and clear away harmful substances – Destroy microbes and block their further invasion |
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stages of inflammation
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1. injury/immediate reactions
2. vascular reactions 3. edema and pus formation 4. resolution/scar formation |
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early inflammatory events
• Controlled by nervous stimulation, chemical mediators, and cytokines released by blood cells, tissue cells, and platelets in the injured area • Vasoactive mediators affect the endothelial cells and smooth muscle cells of blood vessels • Chemotactic factors (chemokines) affect white blood cells • Cause fever, stimulate lymphocytes, prevent virus spread, and cause allergic symptoms • Arterioles constricted at first but quickly vasodilation takes place |
vascular changes
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Leakage of Vascular Fluid into
Tissues; Contains plasma proteins, blood cells, and cellular debris • May be clear (serous) or may contain red blood cells or pus |
edema
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the fluid that escapes through gaps in
the walls of postcapillary venules |
exudates
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Accumulation of exudates causes
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edema
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how WBCs leave the blood vessels and into tissue spaces
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diapedesis
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the tendency of WBCs to migrate in response to a specific chemical stimulus
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chemotaxis
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attracts a collection
of monocytes, lymphocytes, and macrophages to the reaction site |
Long-lived inflammation
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clear pus, cellular debris, dead
neutrophils, and damaged tissue |
macrophages
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produce antibodies
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B lymphocytes
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kill intruders directly
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T lymphocytes
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Late in the process the tissue is repaired or replaced by connective tissue
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scar
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An Adjunct to Inflammation
• An abnormally elevated body temperature |
fever
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fevers of unknown origin
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FUO
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– Pyrogen sets the hypothalamic “thermostat” to a
higher setting • Muscles increase heat production • Peripheral arterioles decrease heat loss through vasoconstriction – Pyrogens can be exogenous or endogenous |
initiation of fever
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Benefits of Fever
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• Inhibits multiplication of temperaturesensitive
microorganisms • Impedes the nutrition of bacteria by reducing the availability of iron • Increases metabolism and stimulates immune reactions and naturally protective physiological processes |
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Cornerstone of
Inflammation and Specific Immunity • General activities – Survey the tissue compartments and discover microbes, particulate matter, and injured or dead cells – Ingest and eliminate these materials – Extract immunogenic information (antigens) from foreign matter |
phagocytosis
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3 kinds of phagocytes
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1. neutrophils
2. monocytes 3. macrophages |
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Antiviral Cytokines and Immune Stimulants; involved against viruses, other microbes, in immune regulation and intercommunication; three classes: All three classes produced in response to viruses, RNA,
immune products, and various antigens • Bind to cell surfaces and induce changes in genetic expression • Can inhibit the expression of cancer genes and have tumor suppressor effects |
interferons (IFN)
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3 major types of interferons
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1. interferon alpha
2. interferon beta 3. interferon gamma |
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A Versatile Backup
System • At least 26 blood proteins that work in concert to destroy bacteria and certain viruses • Cascade reaction • Three different pathways that all yield similar end results |
complement
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3 pathways of the complement system
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– Classical pathway
– Lectin pathway – Alternative pathway |
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activated by anitbodies bound to an anitgen
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classical
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activated by mannan
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lectin
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activated by bacterial or fungal cell wall, viruses, and parasite surfaces
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alternative
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makes a hole in the bacteria where water can go in so it will lyse
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MAC (membrane attack complex)
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complement cascade
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• Initiation
• Amplification and cascade • Polymerization • Membrane attack |
