Immunology Flashcards
(33 cards)
List the 1st line barriers of the immune response
skin, acid, bile mucus
List the non-specific external defense
barriers - skin
traps - mucous membrane, ear wax, cilia
elimination - coughing, sneezing, urination
unfavourable environment - stomach acid, sweat, saliva, urine
lysozyme enzymes - tears, sweat, dissolve bacterial cell walls
Describe the non-specific inflammatory response
- damaged cell walls release histamine
- causes blood vessels to become leaky
- phagocytic white blood cells arrive at the site of damage
- WBCs eat antigens and present part of the antigen on their surface
What is innate immunity?
- present before exposure to any pathogens
- active from birth
- non-specific response to pathogens
- present in all animals and plants
- comprises 1st and 2nd line of defense
What is the specific immune response?
- antibody generation
- specific proteins against individual targets
- y-shaped proteins
What is adaptive immunity?
- develops after exposure to agents such as microbes, toxins or other foreign substances
- highly specific response to each individual pathogen
- present in vertebrates only
- 3rd line of defense (antibodies, lymphocytes)
What are primary lymphoid organs and where are they found?
- development and maturation of immune cells
- bone marrow –> production of haematopoietic stem cells (HSCs), differentiation of HSCs to immune cells
- thymus –> T-lymphocyte maturation and selection
Whare are the secondary lymphoid organs?
- spleen
- lymph nodes
- mucosal associated lymphoid tissue
- generation and organisation of immune response
What is active immunisation?
- occurs naturally when a pathogen enters the body
- induced when antigens are introduced to the body via a vaccination
What is passive immunisation?
- conferred naturally when antibodies cross from mother to foetus across a placenta or in breast milk
- provides immediate short term protection
- can be conferred artificially by injecting antibodies into a non-immune individual
What are humoral defenses?
- antibodies
- made by B-lymphocytes
- detect bacteria and viruses
What are the purpose of antigens?
act as flags to alert adaptive immune response
What are B-lymphocytes?
- develop and mature in bone marrow
- develops ability to identify friend from foe
- immune-competence
- self-tolerance
- each has its own membrane bound receptor
List the functions of antibodies
- opsonisation
- neutralisation
- agglutination
- innate immune recruitment
- activation of complement system
- T-lymphocyte recruitment
What are MHCs?
when phagocytes engulf a pathogen they display part of the organism on their surface
Which cells can present MHCs?
Macrophages, dendritic cells and B cells
What are T lymphocytes?
- made in bone marrow but mature in thymus
- CD4+ helper cells and CD8+ cytotoxic cells
What are CD4+ helper cells and what are their function?
- function as activators of other cells
- naive helper T cells have receptors that identify a unique combination of MHC2 and peptide
- activated CD4s clone to helper and memory T cells
- raise alarm via cytokines
- activates other CD4s to amplify signal/response
- activate CD8s
How do CD4s function?
- cytokines activate other T-lymphocytes
- finish activation of B-lymphocytes
- B cell receptors randomly generate
- B cell interacts with protein, engulfs and presents peptide
- T helper cell inspects B cell
- If CD4 binds to B cell it releases cytokines and activates B cell leading to antibody production
What are CD8 cytotoxic cells and what is their function?
- roam body looking for diseased cells
- fragments displayed in MHC1
- cytotoxic cells bind to MHC1 and peptide
- CD8s release enzymes that punch holes in disease cells - perforin, granzymes
- triggers apoptosis
What are regulatory T cells and what is their function?
- subset of CD4+ cells
- release inhibiting cytokines
- prevents adaptive system from producing too many antibodies or cytotoxic cells that can cause damage to self
List some examples of autoimmune diseases
diabetes - insulin producing cells
rheumatoid arthritis - cartilage and bone
multiple sclerosis - neural myelin
How does HIV affect the immune system?
invades CD4 cells - reduces numbers
What is the purpose of inflammation?
- response to tissue damage or microbial invasion
- brings phagocytes to the injures area
- isolate, destroy and inactivate invaders
- remove debris
- prepare subsequent healing
