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BIO202 - Chapter 21: Lymphatic and Immune Systems

Terms in this set (116)

Immune System
Population of cells that inhabit all of our organs and defend the body from agents of disease; not an organ system
Lymphatic System
Population of cells especially concentrated in the true organ system
Fluid Recovery, Immunity, Lipid Absorption
3 Functions of the Lymphatic System
Lacteals
Lymphatic vessels in the small intestine that absorb dietary lipids that are not absorbed by the blood capillaries
Lymph
Clear, colorless fluid, similar to plasma, but much less protein; recovered fluid of the lymphatic system
Lymphatic Vessels
Transport the lymph from interstial spaces (tissues) to the bloodstream
Nodes, Tonsils, Thymus, Spleen
4 Major Lymphatic Organs
Lymphatic Capillaries - Collecting Vessels - 6 Lymphatic Trunks - 2 Collecting Ducts - Subclavian Veins
Route of Lymph Flow
Cisterna Chyli
Sac in the abdomen that receives lymph; Begins thoracic duct
Thoracic Duct
Left collecting duct that empties into the left subclavian vein
Lymphatic Duct
Right collecting duct that empties into the right subclavian vein
Low Pressure
Causes lymph to flow at a slower speed than venous blood
Exercise
Can significantly increase lymphatic return
Skeletal Muscle Pump
Aids the flow of lymph
NK Cells, T Cells, B Cells, Macrophages, Dendritic Cells, Reticular Cells
6 Types of Lymphatic Cells
Natural Killer Cells
Large lymphocytes that attack and destroy bacteria, transplanted tissue, host cells infected with viruses or have turned cancerous; Responsible for immune surveillance
T Lymphocytes
Lymphatic cells that mature in the thymus and become immunocompetent
B Lymphocytes
Lymphatic cells that when activated causes proliferation and differentiation into plasma cells that produce antibodies
Macrophages
Develop from monocytes; Phagocytize tissue debris, dead neutrophils, bacteria, and other foreign matter; Antigen Presenting Cells
Dendritic Cells
Branched, mobile APCs found in the epidermis, mucous membranes, and lymphatic organs; Alert immune system to pathogens that have breached their surface
Reticular Cells
Branched stationary cells that contribute to the stroma of a lymphatic organ; Act as APCs in the thymus
Lymphatic (Lymphoid) Tissue
Aggregations of lymphocytes in the connective tissues of mucous membranes and various organs
Diffuse Lymphatic Tissue
Lymphocytes are scattered, rather than densely clustered in mucous membranes and connective tissue of many organs; Found in respiratory, digestive mucosa, urinary, and reproductive tracts; Associated with MALT
MALT
Found in digestive layers; Associated with diffuse lymphatic tissue
Lymphatic Nodules
Dense masses of lymphocytes and macrophages that congregate in response to pathogens
Peyer Patches
Dense clusters in the ileum, the distal portion of the small intestine
Primary Lymphatic Organs
Sites where T and B cells become immunocompetent
Red Bone Marrow, Thymus
2 Primary Lymphatic Organs
Immunocompetent
Able to recognize and respond to antigens
Secondary Lymphatic Organs
Immunocompetent cells populate these tissues
Lymph Nodes, Tonsils, Spleen
3 Secondary Lymphatic Organs
Red Bone Marrow
Lymphatic organ involved in hemopoiesis and immunity
Thymus
Member of the endocrine, lymphatic, and immune systems; Houses developing T cells; Goes through involution; Location where T cells become immunocompetent
Lymph Nodes
Most numerous lymphatic organs; Cleanses the lymph and act as a site of T and B cells activation
Tonsils
Patches of lymphatic tissue located at the entrance to the pharynx
Tonsilar Crypts
Deep pits of the tonsils lined with lymphatic nodules where pathogens enter in and encounter lymphocytes
Palatine, Lingual, Pharyngeal (Adenoid)
3 Main Sets of Tonsils
Palatine Tonsils
Pair of tonsils at posterior margin of oral cavity (most often infected) - visible to naked eye
Lingual Tonsils
Pair of tonsils at the root of the tongue
Pharyngeal (Adenoid) Tonsil
Single tonsil on the wall of the nasopharynx; Intercepts inhaled pathogens
Spleen
The body's largest lymphatic organ; Functions in blood production in the fetus, as a blood reservoir, in RBC disposal, and monitors blood for foreign antigens; Highly vascular and vulnerable to trauma and infection
Red Pulp
Sinuses of the spleen filled with erythrocytes
White Pulp
Lymphocytes, macrophages surrounding small branches of splenic artery
Pathogens
Environmental agents capable of producing disease
External Barriers
Make up the first line of defense against pathogens
Second Line of Defense
Nonspecific defense mechanisms; Leukocytes and macrophages, antimicrobial proteins (lysozymes), immune surveillance, inflammation, stomach acid, and fever
Third Line of Defense
The immune system; results from prior exposure, defeats specific pathogen, and leaves the body a 'memory' of it so it can defeat it faster in the future (vaccine)
Nonspecific Resistance
Guards equally against a broad range of pathogens; effectiveness does not depend on prior exposure (first and second lines of defense)
Immunity
Specific defense because it results from prior exposure to a pathogen; usually provides future protection only against that particular one (vaccine)
Acid Mantle
Thin film of lactic acid from sweat which inhibits bacterial growth
Lysozyme
Enzyme that destroys bacterial cell walls
Phagocytes
Phagocytic cells with voracious appetite for foreign matter
Neutrophils
Highly mobile phagocytes that water in connective tissue killing bacteria; Create a killing zone by degranulation and respiratory burst
Degranulation
Lysosomes discharge contents into tissue fluid
Respiratory Burst
Neutrophils rapidly absorb oxygen and creates toxic chemicals
Eosinophils
Phagocytes that stand guard against parasites and allergens; Limit action of histamine and other inflammatory chemicals; Found in mucous membranes
Basophils
Phagocytes that secrete histamine and heparin
Histamine
Vasodilator secreted by basophils
Heparin
Inhibits the formation of clots; Anticoagulant secreted by basophils
Leukotrienes
Activate and attract neutrophils and eosinophils
Lymphocytes
T cells, B cells, and NK cells
Monocytes
Emigrate from the blood into the connective tissue and transform into macrophages
Interferons, Complement System
Two Families of Antimicrobial Proteins
Interferons
Secreted by certain cells infected by viruses; Alert neighboring cells (NK cells and macrophages) and protect them from becoming infected
Complement System
A group of 30 or more globular proteins that make powerful contributions to both nonspecific resistance and specific immunity
Classical, Alternative, Lectin
3 Routes of Complement Activation
Classical Pathway
Route of the complement activation that requires an antibody molecule to get started; Part of specific immunity
Alternative Pathway, Lectin Pathway
Routes of the complement activation that are nonspecific and do not require an antibody
Inflammation, Immune Clearance, Phagocytosis, Cytolysis
4 Mechanisms of Action of Complement Proteins
Immune Clearance
Macrophages of the liver and spleen strip off and destroy the Ag-Ab complexes leaving RBCs unharmed (clearing foreign antigens from the bloodstream)
Opsonization
Coats microbial cells and serves as binding sites for phagocyte attachment (aids in phagocytosis by making the foreign cell more appetizing)
Cytolysis
Mechanism of complement system that forms a hole in the target cell, electrolytes leak out, water flows in rapidly and the cell ruptures
Immune Surveillance
Process in which natural killer cells release perforins that form a hole in the target cells plasma membrane and secrete granzymes that induce apoptosis
Perforins
Proteins that polymerize a ring and create a hole in the plasma membrane of a target cell
Granzymes
Degrading enzymes that induce apoptosis
Fever
An abnormally elevation of body temperature; Stimulates neurons in the hypothalamus that raises the set point for body temperature
Pyrogens
Fever producing agents
Onset, Stadium, Defervescence
3 Stages of Fever
Inflammation
Local defensive response to tissue injury of any kind, including trauma and infection
Redness, Swelling, Heat, Pain
4 Cardinal Signs of Inflammation
Cytokines
Class of chemicals that regulate inflammation and immunity
Mobilization, Containment, Tissue Cleanup
3 Stages of Inflammation
Margination
Adhesion of the leukocytes to the vessel wall; Occurs during inflammation
Diapedesis (Emigration)
Leukocytes squeeze through gaps in the endothelial cells and enter tissue fluid; Occurs during inflammation
Specificity, Memory
2 Characteristics that Distinguish Immunity from Nonspecific Resistance
Cellular, Humoral
2 Types of Immunity
Natural Active Immunity
Production of one's own antibodies or T cells as a result of infection or natural exposure to an antigen
Artificial Active Immunity
Production of one's own antibodies or T cells as a result of vaccination against disease
Natural Passive Immunity
Temporary immunity that results from antibodies produced by another person; Fetus acquires antibodies from mother through placenta
Artificial Passive Immunity
Temporary immunity that results from the injection of immune serum from another person or animal; Antivenum for a snake bite
Antigen
Any molecule that triggers an immune response; Complex molecule with structures unique to the individual
Epitopes
Certain regions of an antigen molecule that stimulate immune responses
Clonal Deletion, Anergy
2 Forms of Negative Selection
Clonal Deletion
Self-reactive T cells die and macrophages phagocytize them (Negative Selection)
Anergy
Self-reactive T cells remain alive but unresponsive (Negative Selection)
Positive Selection
2% of T cells that pass the test multiply to form clones of identical T cells programmed to respond to a specific antigen
MHC Proteins
Act as cell 'identification tags' that label every cell of your body as belonging to you
Cellular Immunity
A form of specific defense in which the T lymphocytes directly attack and destroy diseased or foreign cells, and the immune system remembers the antigens and prevents them from causing disease in the future
Cytotoxic, Helper, Regulatory, Memory
4 Classes of T Cells Involved in Cellular Immunity
Cytotoxic T Cells
Killer T cells, carry out attack on enemy cells
Helper T Cells
Help promote cytotoxic T cell and B cell action and nonspecific resistance
Regulatory T Cells
Inhibit multiplication and cytokine secretion by other T cells; Limit immune response
Memory Cells
Responsible for memory in cellular immunity for future exposure to an antigen
Recognition, Attack, Memory
3 Stages of Both Cellular and Humoral Immunity
Recognition
Phase of immunity that includes antigen presentation and T cell activation
Attack
Phase of immunity in which the helper T cells secrete interleukins that attract neutrophils, NK cells, and macrophages; Cytotoxic cells deliver a lethal hit of toxic chemicals
Costimulation
The double checking of the T ell to see if it is really bound to a foreign antigen
Memory
Phase of immunity in which some cytotoxic and helper T cells develop a recall so as to issue a quick attack upon re-exposure to the same pathogen later in life
Humoral Immunity
Indirect method of specific immunity in which B lymphocytes produce antibodies that bind to antigens and tag them for destruction by other means
Immunoglobulin
A defensive gamma globulin found in the blood-plasma, tissue fluids, body secretions, and some leukocyte membranes; Antibody
Antibody Monomer
Basic structural unit of an antibody; Composed of four polypeptide chains: two larger heavy chains and two light chains
IgA
Monomer in plasma; Provides passive immunity to newborns
IgD
Monomer which functions in B cell activation
IgE
Monomer that stimulates the release of histamine and other chemical mediators of inflammation
IgG
Monomer that constitutes 80% of circulating antibodies
IgM
Largest antibodies; Secreted in primary immune response, agglutination, and complement fixation
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