The Immune System Flashcards
What does the lymphatic system consist of
Lymphatic tissue
Bone marrow
Lymph
Lymphatic vessels
What does the lymphatic system do?
Protects us against disease
Lymphoid cells respond to
- environmental pathogens
Toxins
Abnorma body cells such as cancers
To produce, maintain and distribute lymphocytes
Return of fluid and solutes from peripheral tissue to blood
Distribute hormones, nutrients and waft produces from tissue of origin to circulation
What are the pathogens that can cause disease
Viruses
Bacteria
Fungi
Parasites
Explain the 4 parts of the lymphatic system
Lymph - similar to plasma without plasma proteins
Lymphatic vessels - carry lymph from peripheral tissues to venous system
Lymphoid tissues e.g lymph nodes and lymphoid organs e.g thymus, spleen, bone marrow
Lymphoid cells (lymphocytes, phagocytes)
Where is thymus
Behind spleen
Where are lymphocytes produces
Lymphoid tissues
Lymphoid organs
Red bone marrow
What do lymphocytes do
Detective problems
Travel to site of injury or infection
Explain lymphatic vessels and capillaries
Vessels begin as capillaries which are closed at one end
L capillaries located between cells of many tissues
Merge to form vessels which have thin walls and many vessels
What are the differences between lymphatic vessels and blood capillaries
Start as blind pockets rather than tubes
Have large diameters
Thinner walls
Flat or irregular in section
What stops backflow of lymphatic fluids
Valves in lymphatic vessels
Explain lymph trunks and ducts
From the lymphatic vessels, lymph passes through lymph nodes and then into lymph duct
Trunks: lumbar, intestinal, bronchomefiastinal, subclavian and jugular trunks
Lymph trunks then merge to form thoratic duct or right lymphatic duct
What does the right lymphatic duct do
Clear from upper right quadrant
What are the kinds of circulating lymphocytes
T cells: thymus dependent
B cells: bone marrow derived
NK cells: natural killer cells, bone marrow derived
What can red bone marrow cells become?
Lymphoid stem cells
Then either:
Natural killer or b cells
Migrate to thymus then T cells
Okay are the primary lymphatic organs
Where they become immunocompitant
Red bone marrow
Thymus
Okay are the primary lymphatic organs
Where they become immunocompitant
Red bone marrow
Thymus
What are the secondary lymphatic organs
Lymph nodes
Spleen
Lymphoid nodules
Explain the structure of a lymph node
Afferent vessels - coming in
Efferent vessels- leaving (fluid)
Germinal centre - where b cells mature and produce antibodies
What is the difference between lymph organs and lymphoid nodules
Lymph organs (lymph nodes, thymus, spleen) are separated from surrounding tissue by fibrous capsule
Nodule = bundle of tissue without fibrous capsule
E.g tonsils, appendix, digestive system
Explain the flow of lymph
Interstitial fluid
L capillaries
L vessels
L trunks
L ducts
Subclavian veins
Explain how fluid flows through lymph node sinuses
Subcapsular space
Outer cortex
Deep cortex
Core
Hilium and efferent lymphatics
What does the lymph node do
Filter lymph before returns to venous circulation
Removes debris, pathogens, antigens
Where are the lymph nodes (glands
Groin and base of neck
What is lymphadenopathy
Chronic enlargement of nodes
Infection/endocrine disorder/ cancer
What is innate vs specific immunity
Innate - non specific
Adaptive- specific
What is non specific immunity
Block any potential pathogens
Present from birth
No memory
What is specific immunity
Identify and attack and develop immunity to specific antigen
Acquired response to antigen
What are the 7 categories aif non specific defence
Physical barriers
Phagocytic cells
Immunological surveillance (no cells)
Interferons (antiviral)
Complement system
Inflammation
Fever
What are the physical barriers
Tears
Skin -
Anatomic barrier, sweat and sebum
Anti microbial secretions e.g lactic and ffas
Low ph
Urine
Acidic
Stomach acid
Enzymes
Respiratory
Mucosa
Ciliated epithelium
Antibodies
Phagocytes
Explain phagocytosis and antigen presentation
Engulphs pathogen
Lysozyme breaks it up
Antigen binds
Antigen then binds to cell membrane
What are the classes of phagocytes
Phagocytic cells: remove debris and pathogens
Macrophages -
Neutrophils and eosinophils
Leave bloodstream
Enter peripheral tissue to fight infection
Macrophages
Distributed throughout body
Make up monocyte macrophage system
Fixed or free
Explain activated macrophages
Engulf and destroy pathogen with lysosomal enzymes
Bind to pathogen so other cells can destroy it
Destroy by releasing toxic chemicals to interstitial fluid
Explain immunological surveillance by nk cells
- Recognition and adhesion
- Realignment of Golgi apparatus
- Secrete perforin
4, lysis of abnormal cell
Explain anti viral interferons
Interferons = proteins released by lymphocyte and macrophage
Alpha stim nk
Beta slow inflammation
Gamma stim macrophage
Explain the complement system
Enhances ability of phagocytes ans antibodies to clear pathogen
What are the effects of complement activation
- Attract phagocytes
- Enhance them
- Stim inflammation
- Destroy target cell membrane
Explain inflammation and tissue repair
More blood flow
Mast cells release histamine
Phagocytes move to site
Neutophils move to cite
Clot
Activate fibrinogen
Explain fever
Increase body temp due to release of pyrogens
Mobilises defences
Accelerated repair
Inhibits pathogens
What are the two main divisions of specific immunity
- Cell mediated immunity T cells
T cells only recognise fragments of antigenic proteins that are processes and presented in a certain way - Humoral or antibody mediated immunity (B cells)
B cells can recognise and bind to antigens in lymph, interstitial fluid or blood plasma
What are MHC proteins
Class one
On all nucleated cells
Two
Antigen presenting cells
Lymphocytes
How does the specific immune system recognise foreign antigens
Free living - exogenous
Inside host cells - endogenous
White blood cells differentiate self antigens - expressed on cell surface
Non self antigens - presented on cell surface
Explain cell mediated immunity
Mediated by T cells
3 main types of T cells
- Cytotoxic - cell mediated immunity, destroy virally infected cells
- Helper T cells - stimulate function of T and b cells
- Suppressor T cells - inhibits T and B
Explain humoral immunity
Mediated by B cells
Attack antigens by producing specific antibodies
Explain humoral immunity
Mediated by B cells
Attack antigens by producing specific antibodies
What are the 5 types of antibodies
IgG- (80% of all antibodies, placental transfer)
IgA- glandular secretions e.g mucus, saliva, breast milk
IgM-
igD
IgE
Explain allergies
Hypersensitivity
IgE
Explain autoimmune disorder
Immune system fails to display self tolerance and attacks own tissue
Explain diseases of the immune system
SCID
HIV
