BIO 254 Quiz GET AN A (100% Correct) Questions with Accurate Answers.

BIO 254 Quiz GET AN A (100% Correct) Questions with Accurate Answers. Functions of lymphatic system - Fluid balance - Lipid absorption - Immunity/defense Lymphatic pathway: Begins at Lymphatic capillaries Lymphatic pathway: capillaries to Afferent lymphatic vessels Lymphatic pathway: afferent lymphatic vessels to Lymph nodes Lymphatic pathway: lymph nodes to Efferent lymphatic vessels Lymphatic pathway: efferent lymphatic vessels to Lymphatic trunk Lymphatic pathway: lymphatic trunk to Lymphatic collect ducts Lymphatic pathway: lymphatic collecting ducts to Subclavian vein Lymphatic capillaries - Microscopic, close-ended - Thin walled of simple squamous epithelium - Tissue fluid that enters is called lymph Lymphatic vessels - Walls similar to veins but thinner - SL valves that allow 1-way flow Lymphatic trunk - Drains lymph from specific body areas - Named for region served: lumbar, intestinal, intercostal, tubular, subclavian, bronchomediastinal Lymphatic collecting ducts - Drains lymph from trunk - 2 for entire lymph system Thoracic duct - Long & wide - Drains majority of body - Begins at sac called cisterna chyli - Empties into left subclavian vein Right lymphatic duct - Smaller - Begins in right thorax - Empties into right subclavian vein - Drains upper right portion of body Lymph Tissue fluid that has entered lymphatic capillaries Tissue fluid formation Blood plasma - plasma proteins Lymph formation prevents Edema Lymph flow is affected by - Skeletal muscle compressing blood vessels - Respiration/inspiration - Smooth muscle of lymphatic vessels Valves of the lymphatic vessels Prevent backflow Role of lymphatic capillaries - Absorb dietary fats in small intestine - Return of small proteins to blood - Collection of excess interstitial fluid & delivery to blood - Delivery of foreign particles to lymph nodes Lymphatic tissue - MALT (mucosa-associated lymphatic tissue) - Unencapsulated: digestive, respiratory, urinary, reproductive tracts - Lymphatic nodules are compact mass: tonsils, appendix - Peyer's patches: nodules in ileum Lymphatic organs - Encapsulated - Nodes, thymus, spleen Lymph nodes - Organ - Bean-shaped found along vessels - Not in central nervous system - Filter lymph w/ lymphocytes & macrophages - Immune surveillance Thymus - Organ - Houses lymphocytes - Bi-lobed gland in mediastinum - Most cells are inactive & called thymocytes - Turns thymocytes into T-cells using thymosin - Large in infancy/childhood, shrinks at puberty, small in adult - Replaced w/ adipose & connective tissue in elderly Spleen - Largest organ - Houses macrophages - Looks like large node in upper left of abdominal cavity - Contains venous sinuses filled w/ blood - 2 tissue types: white & red pulp - Filters blood w/ lymphocytes & macrophages - Breaks down worn-out RBCs Red pulp of spleen Contains RBCs, lymphocytes, macrophages White pulp of spleen Contains lymphocytes Immune mechanisms - Innate (nonspecific) - Adaptive (specific) Innate defenses - General - Protect against many types of pathogens - 1st & 2nd line Adaptive defenses - Targets specific antigens - Carried out by lymphocytes/macrophages that recognize specific antigens - "Self" from "nonself" - 3rd line Types of innate defenses - Species resistance - Mechanical barriers - Inflammation - Chemical barriers - NK cells - Phagocytosis - Fever Types of adaptive defenses - Cellular - Humoral Species resistance of innate defenses Lack of receptors, temperature, or chemical environment needed by pathogen Mechanical barriers of innate defenses - 1st line - Skin, mucus membranes - Prevent entry Inflammation of innate defenses - 2nd line - Local redness, swelling, heat, pain - Walls off infection to prevent spread - WBCs gather & destroy pathogens via phagocytosis - Clotting factors/fibrinogen form fibrin network - Phagocytes engulf/destroy after infection is under control - Lost cells replaced via cell division The redness of inflammation is caused by Vasodilation The swelling of inflammation is caused by Capillary permeability & fluid entry into tissue spaces The heat of inflammation is caused by Blood arriving at site from deep areas of the body The pain of inflammation is caused by Receptors at the site Chemical barriers of innate defenses - 2nd line - Enzymes - Interferons - Defensins - Collectins - Complements Interferons - Block viral replication - Stimulate phagocytosis - Tumors Defensins Peptides produced by neutrophils & other granulocytes that make openings in cell membranes/walls Collectins Proteins that protect against many bacteria, yeast & some viruses by binding to microbes Complements Group of proteins in plasma & other body fluids that stimulate inflammation, attract phagocytes, enhance phagocytosis NK cells of innate defenses - 2nd line - Small population of lymphocytes - Secrete cytolytic substances called perforins that lyse cell membranes - Enhance inflammation - Viruses, cancer Phagocytosis of innate defenses - 2nd line - Remove foreign particles from lymph - Occurs in blood vessels & tissues of spleen, liver, bone marrow - Most active cells are neutrophils & monocytes - Chemotaxis: damaged tissues release chemicals that attract phagocytic cells - Monocytes that leave blood become macrophages which can be free or fixed Fever of innate defenses - 2nd line - Lymphocytes proliferate & produce cells that secrete interleukin-1 (IL-1) which raises thermoregulation set point - Increased temp inhibits microbial growth causing liver & spleen to take up iron needed by pathogens - Increased temp increases phagocytic activity IL-1 Endogenous pyrogen Pathogen Disease causing agent Antigen - Nonself molecule that triggers an immune response - Lymph system responds to nonself - Lymphocyte receptors enable recognition - Most effective are large & complex - Can be proteins, polysaccharides, glycoproteins, glycolipids Cellular immune response of adaptive defenses - Immune cells Humoral immune response of adaptive defenses - Antibodies Lymphocyte origins - Red bone marrow release unspecialized - 2 types are T & B cells - 1/2 settle in thymus, specialize, become T-cells - 1/2 differentiate in red bone marrow & become B-cells T-cells - Originate in red bone marrow - Specialize in thymus - Found in lymphatic tissues & 70%-80% in bloodstream - Cellular immune response - Interact directly w/ antigens B-cells - Originate & mature in bone marrow - Found in lymphatic tissues & 20%-30% in bloodstream - Humoral immune response/antibody-mediated immune response - Activation requires cytokines from T-cells - Some become memory cells & plasma proteins - Interact indirectly by producing antibodies Cytokines Secreted by T-cells during cellular immune response which enhances response to antigens Types of specialized T-cells - Helper - Cytotoxic - Memory Helper T-cells Activate other cells Cytotoxic T-cells Attack foreign/cancer cells Memory T-cells Provide future immunity Antibody molecules - Gamma globulins/immunoglobulins - Y shaped globular proteins composed of 4 amino acid chains - Antigen specific Types of antibodies - IgG - IgM - IgA - IgD - IgE IgG antibodies - 80% - Bacteria, viruses, toxins - In plasma & tissue fluids - Activate compliments IgA antibodies - 13% - Exocrine gland secretion IgM antibodies - 6% - Food, bacteria - In plasma - Activate complements IgD antibodies - 1% - On B-cell surface - Activates B-cell - Proliferant in infants IgE antibodies - 1% - Exocrine gland secretion - Inflammation, allergic response Primary immune response - 1st antigen exposure - B & T cells specific for antigen activate - Plasma cells release IgM then IgG - Antibodies appear in 5-10 days & remain for weeks - Memory B-cells produced Secondary immune response - Subsequent exposure to same antigen - Produce a lot in 1-2 days - Accomplished by memory B & T cells - Antibodies remain months/years - Memory B-cells live for years Naturally acquired immunity - Live pathogen exposure - Mother to fetus Artificially acquired immunity Via injection/vaccine Passive immunity - Temporary via antibodies - No antigen exposure - No immune response Active immunity - Permanent via antigen contact - Immune response - Memory B-cells produced