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61 Cards in this Set
- Front
- Back
What does the lymphatic system consist of?
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Lymphatic tissues and organs & lymphatic vessels.
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What are the characteristics of lymph?
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excess tissue fluids carried by the lymphatic vessels
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When does the fluid become lymph?
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When it enters the lymph vessels.
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What is the primary cause for the reabsorption of the excess fluids?
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Increased osmotic pressures forces water reabsorption into the capillaries and forces it into the lymph vessels.
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What are the properties of lymphatic vessels?
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One way system to heart. No pump
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Characteristics of lymph capillaries
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Walls overlap, form flap-like minivalves that close from higher pressure intracapillary to hold fluid inside. Anchored to connective tissue by filaments.
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What materials are in lymph?
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H2O, blood, proteins, bacteria, viruses, cancer cells, cell debris.
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What do lymph nodes do?
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Filter lymph before returning it to blood. Macrophages engulf and lymphocytes provide immune response to eliminate harmful products.
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Lymph node structure
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Kidney shaped, <1 inch long. Cortex: outer part, contains follicles (lymphocytes here). Medulla: inner part, contains macrophages.
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Flow of lymph through nodes
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Enters in convex side via afferent vessels, flows thru sinuses inside, exits thru efferent lymphatic vessels. More afferent than efferent vessels.
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Other lymphoid organs
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Spleen, thymus, tonsils, Peyer's patches (intestinal)
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What does the spleen do and its location?
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Filters blood, destroys worn out cells (most important function), forms blood cells in fetus, acts as blood reservoir.
Left side of abdomen |
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Location and function of thymus
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Located low in pharynx (throat), overlying the heart. Functions at peak levels only during childhood. Produces hormones to program lymphocytes.
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What do tonsils do?
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Trap and remove bacteria and other foreign materials. Tonsillitis is caused by congestion w/ bacteria.
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Location and function of Peyer's patches
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Found in wall of small intestines. Resemble tonsils in structure, capture and destroy bacteria in intestine.
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What is the immune system also known as?
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Specific body defense system, for each type of invader to the body.
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What are Non-specific body defense types?
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Skin, mucous membranes, specialized cells, chemicals produced by the body (lysosome,cerumen), fevers.
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What are the components of the first line of defense?
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Skin and mucous membranes
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How does the skin protect?
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Physical barrier, pH is acidic, sebum is toxic to bacteria, vagial secretions are very acidic.
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How do the mucous membranes protect?
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Stomach mucosa: secretes HCL & pepsin (protein digesting enzyme). Saliva & lacrimal fluid contain lysozyme. Mucus traps microorganisms.
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What is the 2nd line of defense?
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Specialized cells and inflammatory response.
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What types of cells for defense?
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Phagocytes: (macrophages, neutrophils).
Natural killer (NK) cells |
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How do NK cells work?
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Unique lymphocytes that can fight before the immune system starts. React against any target by recognizing surface sugars. Secrete surface lytic: perforin
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How does the inflammatory response work?
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Tissue injury triggers, chain of events leads to protection & healing. Prevents agent spread, disposes of cell debris, sets up repairs.
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What are the cardinal signs of inflammatory response
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Redness
Heat Swelling Pain Loss of function |
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What is a Complement?
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Group of 20+ plasma proteins. Activated when they encounter & attach to cells(complement fixation) Damage foreign cell surfaces. Has vasodilators, chemotaxis, opsonization.
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What does Interferon do?
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Binds to healthy cells surfaces to inhibit viruses binding. Proteins of virus-infected cells, diffuse to nearby cells and bind to membrane receptors.
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Fever
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Higher body temperature,pyrogens reset hypothalmus heat regulation, iron & zinc release inhibited, none for bacteria growth. Increases tissue repair speed
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What is the 3rd line of defense?
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The immune system, specific defenses.
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Antigen specific
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Recognizes and act against particular foreign substances.
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Is it only a local immunity?
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Systemic, has memory that recognizes and mounts a stronger attack on previously encountered pathogens.
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Types of Immunity
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Humoral: anti-body mediated, cells produce chemicals.
Cellular: Cell-mediated, cells target virus infected cells. |
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What are non-self antigens?
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Any substance capable of exciting the immune system and provoking an immune response.
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What are self-antigens?
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Cells restricted to one's own body; can attack someone else's cells if placed in another person. (Organ transplants)
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Allergies (hypersensitivity)
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Abnormally vigorous immune response to a "perceived" threat that damages tissue to fight off something that would be harmless to body.
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Lymphocytes: Types
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Originate from hemocytoblasts in red bone marrow. B-lymphocytes from bone marrow. T-lymphocytes from thymus gland. Macrophages from monocytes, widely distributed in lymphoid organs.
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Humoral immune response
Primary Humoral Response. |
Anti-body mediated: B-lymphocyte binds to specific antigen. Event activates large number of clones to be made from the first lymphocyte.
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Humoral immune response Secondary humoral response.
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Most B cells become plasma cells produce antibodies to destroy antigen. Activity lasts 4+5 days Some B cells become long lived memory cells; recognizes antigen
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Secondary Response does what?
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Rapid response to second antigen exposure; stronger and longer lasting.
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Active Immunity
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B cells encounter antigens and produce antibodies. Can be naturally or artificially acquired.
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Passive Immunity
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Antibodies from someone else, mother/fetus or from immune serum or gamma globulin. Memory does not occur, protection from "borrowed" antibodies.
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Monoclonal Antibodies
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Antibodies prepared for clinical testing or diagnostic purpose. From a single cell line. Ex: Dx for pregnancy, tx for hepatitis and rabies.
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Antibodies (Immunoglobulins)
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Ig's: Soluble proteins secreted by B cells, carried in blood plasma. Binds specifically to an antigen.
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Antibody Structure
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4 amino acid chains linked by disulfide bonds; heavy chain and light chain. Specific antigen binding sites are present.
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Antibody Classes
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IgM: can fix complement
IgA: found in mucus IgD: for activation of B cells IgG: cross placental barrier IgE: allergies involvment |
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Antibody Function
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Inactivate antigens by:
complement fixation, neutralization, agglutination, precipitation. |
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Cellular Immune Response
Antigen recognition |
antigens must be presented by macrophages to a T cell.
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Double recognition
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T cells must recognize non-self and self antigens. After antigen binding, clones form but different classes of cells produced.
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Types of T cell clones
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Cytotoxic T cells
Helper T cells Suppressor T cells Few members of each clone are memory cells. |
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Cytotoxic T cells
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Kill infected cells, insert a toxic chemical (perforin)
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Helper T cells
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Recruit other cells to fight the invaders. Interact directly w/ B cells
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Suppressor T Cells
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Release chemicals to suppress the activity of T&B cells. Stops the immune response to prevent uncontrolled activity.
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Major types of grafts
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Autografts: same person graft
Isografts: from identical twin Allografts: unrelated person Xenografts: from different animal species. |
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Organ transplants and rejection
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Autografts & isografts are ideal Xenografts never work
Allografts more successful w/ close tissue match. |
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Types of Allergies: Immediate hypersensitivity
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Triggered w/release of histamine form IgE binding to mast cells. Rx w/in seconds of allergen contact. Anaphylactic shock is dangerous, systemic response.
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Types of Allergies: Delayed hypersensitivity
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Triggered by lymphokine release from activated helper T cells. Symptoms apppear 1-3 days after contact w/ antigen. Ex: contact dermatitis
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Disorders of Immunity: Immunodeficiencies
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Production or function of immune cells or complement is abnormal. May be congenital or acquired, includes AIDS.
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Autoimmune Dzs
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Immune system does not recognize self or non-self antigens. Antibodies & sensitized T lymphocytes attack its own tissues.
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Autoimmune Examples
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Mult. Sclerosis
Myasthenia Gravis Juvenille DM Rheumatoid arthritis,SLE, glomerulonephritis |
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Self Tolerance Breakdown
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Inefficient lymphocyte programming; self proteins in circulation not exposed to immune system (eggs, sperm, eye lens); cross reaction - Rheumatic fever
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Developmental aspects of Lymphatic System and Body Defenses
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Lymphoid organs poorly developed before birth, except thymus and spleen. No functioning lymphocytes at birth, passive immunity from mother.
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