Immune System Flashcards
Types of Pathogens
Viruses
Fungi
Bacteria
Parasites
4 Parts of Lymphatic System
Lymph
Lymphatic Vessels
Lymphoid Organs
Lymphocytes/Phagocytes
3 Functions of Lymphatic System
Produce/Maintain/Distribute Lymphocytes
Return of fluid and solutes from peripheral tissues to blood
Distribution of hormones, nutrients and waste products from tissue to circulation
3 Sites of lymphocytes production
Lymphoid Tissues (e.g. Tonsils)
Lymphoid Organs (e.g. Spleen)
Red Bone Marrow
Features of Lymphatic Vessel/Capillary formation
Lymphatic Capillaries are located between cells
Capillaries merge to form vessels
3 Differences between lymphatic/blood capillaries
Lymphatic Capillaries start as blind pockets instead of tubes
Large Diameter
Thinner Walls
Flat or irregular in sections
Pathway of Lympth through structures
Lymph vessels, lymph nodes, lymph trunks, lymph ducts
5 Important Lymph Trunks
Lumbar
Intestinal
Bronchomediastinal
Subclavian
Jugular
Lymph trunk Definition
Collection of Lymph Vessels carrying Lymph
Lymph Duct Definition
Structure used to empty lymph into venous system
2 Lypmh Ducts
Thoracic Duct
Right Lymphatic Duct
3 Types of Lymphocytes
T Cells
B Cells
NK Cells (Natural Killer)
Derivation Origins of Lymphocytes
T Cells - Thymus-dependend
B Cells - bone marrow-derived
NK Cells - bone marrow-derived
Production and Distribution of T Cells (Location, Function)
Hemocytoblasts in Red Bone Marrow form Lymphoid Stem Cell
Lymphoid Stem Cells migrate to thymus
T Cells producted when stem cells in the presence of Thymic Hormones
Distributed to Peripheral Tissue for Cell-Mediated Immunity
Production and DIstribution of B Cells (Location, Function)
Hemocytoblasts in Red Bone Marrow form Lymphoid Stem Cell
Lumphoid Stem Cells differentiate into B Cells via Interleukin-7
Distributed to Peripheral Tissue for Antibody-Mediated Immunity
Production and Distribution of NK Cells (Location, Function)
Hemocytoblasts in Red Bone Marrow form Lymphoid Stem Cell
Differentiate into NK Cells
Distributed to Peripheral Tissues for Immunological Surveillance
Primary Lymphatic Organs/Tissues
Red Bone Marrow
Thymus
Secondary Lymphatic Organs/Tissues
Lymph Nodes
Spleen
Lymphoid Nodules
Structures of a Lymph Node
Medulla
Inner Cortex
Outer Cortex
Germinal Centre
Cells in Medulla
B Cells
Plasma Cells
Macrophages
Cells in Inner Cortex
T Cells
Dendrite Cells
Cells in Outer Cortex
B Cells
Cells in Germinal Centre
B Cells
Follicular Dendritic Cells
Macrophages
Dendritic Cell Definition
Type of antigen-presenting cell
Route of Lymph through Lymph Node (Cell Types at each location)
Subscapular Space - Macrophages, Dendritic Cells
Outer Cortex - B Cells
Inner Cortex - T Cells
Medulla - B Cells, Plasma Cells
Efferent Lymphatic Vessels
Lymph Node Definition and Function
Small structure used to filter out cancer cells and infections
Lymphoid Nodule Definition and Function
Dense masses of lymphocytes and macrophages
Location of Lymphoid Nodules (Example)
Inbetween Mucous Membrane and underlying connective tissue in digestive system
Difference between lymph organs/lymph nodules
Lymph organs separated by fibrous capsule, nodules are not
Flow of Lymph
Interstitual Fluid
Lymph Capillaries
Lymph Vessels
Lymph trunks
Lymph Ducts
Subclavan Veins
Functions of Lymph Node
Filter
Removes Debris, Pathogens, 99% of antigens
Lymphadenopathy Definition
Chroninc/Excessive Enlargement of Lymph Nodes
3 Featuers of Non-Specific Immunity
Block/Attack any potential pathogens
Present from birth
No Memory
2 Features of Specific Immunity
Develops immunity agains specific antigen
Acquired in response to antigens
7 Non-Specific Defenses
Physical Barriers
Phagocytic Cells
Immunological Surveillance (NK Cells)
Interferons
Complement System
Inflammation
Fever
5 Physical Barriers
Eyes
Respiratory Tract
Digestive Tract
Skin
Genitourinary Tract
Process of Phagocytosis
Pathogen engulfed by Antigen-Presenting Cell (APC)
Lysosome action produces antigenic fragments
Antigenic fragments bind to Class II MHC Proteins
Antigenic fragments presented on cell membrane by MHC Proteins
2 Classes of Phagocytes
Microphages
Macrophages
2 Features of Microphages (Examples, Mode of Action)
Neutrophils or Eosinophils
Leave the bloodstream to enter peripheral tissue to fight infection
3 Features of Macrophages (Examples, Distribution, Mode of Action)
Large Phagocytic Cells
Distributed throughout body to make up monocyte-macrophage system
May be fixed or free
4 Steps of Immunological Surveillance by NK Cells
NK cells recognises and binds to abnormal cell
Golgi Apparatus of NK Cell realigns
Perforin secretion into abnormal cell
Lysis of abnormal cell occurs
Interferon Definition and Function
Cytokines released by activated lymphocytes and macrophages
Responsible for non-specific response to viral infection
3 Types of Interferons (Site of production, function)
Alpha - Produced by leukocytes, stimulate NK Cells
Beta - Secreted by Fibrocytes, slow inflammation
Gamma - Secreted by T Cells/NK Cells, Stimulate macrophages
Complement System Definition
Enhances ability of antibodies and phagocytic cells to clear pathogens from an organism
Effects of Complement System
Attracts phagocytes
Enhances phagocytosis
Stimulates inflammation
Destroys target cell membrane
6 Process of inflammation in Tissue Repair
Increased Blood Flow
Mast Cells release histamine
Neutrophils move to site
Neutrophils remove debris
Clot formation
Activation of fibrinogen
Fever Definition
Increases in body temperature due to release of pyrogens
Pyrogen Definition
Material that causes hypothalamus to raise body temperature
Effects of Fever
Mobilises Defences
Accelerates repair
Inhibits pathogens
2 Divisions of Specific Immunity (Cell Type)
Cell-Mediated Immunity - T Cells
Antibody-Mediated Immunity - B Cells
Cell-Mediated Immunity Definition
Recognises fragments of antigenic proteins that are processed and presented in a certain way
Antibody-Mediated Immunity Definition
B Cells recognise and bind to antigens in lymph, interstitial fluid and blood plasma
Function and Types of MHC Proteins
Used to distinguish self and non-self antigens
Class I (Self presenting)
Class II (Non-self presenting)
Exogenous Definition
Free living antibody
Endogenous Definition
Antibody Inside Host Cell
Antigen Expression using Class I MHC
Viral/Bacterial Infection Occurs
Abnormal Peptides released
Class I MHC proteins incorporate abnormal peptides in Golgi
Vesicle transports MHC/Peptide complex
Abnormal Peptide membrane displayed on membrane
3 Types of T Cells (Functions)
Cytotoxic - Destroy Virally Infected Cells
Helper - Stimulate T/B Cell Function
Suppressor - Inhibit Function of T/B Cell
Clonal Selection Definition
Selection of lymphocytes from a population for its antigen specificity during immune response
Activation of T Helper Cell
Inactive T Helper Cell binds to presented MHC II antigen using CD4 Protein
T Helper Cell becomes active
Undergoes Clonal Selection (Proliferation and Differentiation)
Formation of T Helper Cell Clones (Active/Memory Cells)
Activation of Cytotoxic T Cell
Inactive cytotoxic T Cell binds to presented MHC I antigen using CD8 Protein
Costimulation by IL-2 from Helper T Cell occurs during binding
Cytotoxic T Cell activates
Undergoes Clonal Selection (Proliferation and Differentiation)
Formation of Cytotoxic T Cell clones (Active/Memory)
Two mechanisms of Cytotoxic T Cell activity
Granzymes
Granulysin/Perforin
Activity of Cytotoxic T Cells through Granzymes
Recognition and Attachment
Granzymes secreted by T Cell
Apoptosis occurs by Granzymes
Microbes destroyed by phagocytes
Activity of Cytotoxic T Cells through Perforin/Granulysin
Recognition and Attachment
Granulysin and Perforin secreted by T Cell
Perforin causes cytolysis
Microbes destroyed by granulysin
Antibody Structure
2 Binding Sites
2 Heavy Chains linked by Disulfide Bonds
2 Variable segments linked to Heavy Chain via Disulfide Bonds
5 Types of Antibodies (Functions, Most Abundant)
IgG - Enhances phagocytosis, neutralizing toxins, triggers complement system, immune protection in newborns (80%)
IgA - Localized protection of mucous membranes agains bacteria/viruses
IgM - Agglutination and lysis of microbes
IgD - Surface antigens of B Cells
IgE - Allergic and hypersensitivity reactions
Activation of B Cells
B Cell binds with Microbe with surface receptor
Costimulation using T Helper Cell occurs during binding
Clonal Selection
Formation of Plasma Cells and Memory B Cells
Primary Immune Response (Antibody Levels)
IgM released first, followed by IgG antibody
IgM dissipates after 3 weeks, IgG remains in the serum
Secondary Immune Respone (Antibody Levels)
IgG and IgM released at same time
IgG concentration much higher than IgM in response to recognised antigen.
Forms of Immunity (Definition)
Induced Active Immunity - Developed after administration of antigen to prevent disease
Natural Active Immunity - Developed after exposure to antigens in environment
Natural Passive Immunity - Conferred by transfer of maternal antibodies across placenta/in breast milk
Induced Passive Immunity - Conferred by administration of antibodies to combat infection
Problems with Immune System
Allergies
Autoimmune Disease
Transplant Rejection
Allergy Definition
Occurs when a person is overly reactive to a substance
Tissue damage occurs
IgE antibody involved
Autoimmune Disease Definition
Occurs when immune system fails to display self-tolerance, ends up attacking own body tissue
Transplant Rejection Definition
Occurs as a result of body recognising a transplanted organ as non-self and mounting a specific immune response against it
Treated with Immunosuppressants
