Immune Response Flashcards
Describe the areas of the body involved with immunity
- Red bone marrow
- Found in the ends of long bones/iliac crest/sternum
- Produces WBC/ RBC/ platelets - Thymus gland
- Sits in pericardial cavity
- Produces T lymphocytes - Lymph Nodes
- Holding areas for immune cells - Spleen/tonsils
- holding areas for immune cells
Describe the process of cell mediated immunity
- Pre T cells are produced in red bone marrow
- Travel to thymus (become mature t cells)
- Stored in lymphatic tissue as either CD8+ T cells or CD4+ T cells
- CD4+ T cells activate the CD8+ T cells to become killer CD8+ cells when needed - which then leave the lymphatic tissue and attack invading antigen via phagocytosis.
- Memory cells are stored in the lymph system for next time the pathogen invades
Describe the differences between CD4+ T cells and CD8+ T cells
CD8+ T cells (natural killer cells)
- Once activated by CD4+:
> Release Perforin - Causes autolysis (pathogen cell destroys itself)
> Release lymphotoxin - Causing apoptosis (early cell death)
CD4+ cells (helper cells)
- manage and co-ordinate the immune response
- activates CD8+ cells and B cells for both responses
- also act as suppressor cells to slow the immune response.
When would the body use Cell-mediated response vs Humoral response?
- Cell-mediated is vs intracellular pathogens e.g viruses/ cancer cells and transplants
- Humoral = vs extracellular pathogens e.g bacteria
Describe the process of humoral immunity
- Mature B cells are produced by red bone marrow (have specific receptors to pathogens)
- Stored in lymph system until needed
- Activated by CD4+ T cells to become Plasma cells and antibodies (that bind to the pathogen cell receptors - block until dealt with by phagocytosis)
- Memory cells remain in lymph system for next time
Antibodies (Immunoglobulin) can have what actions to deal with pathogens
- Agglutination - Makes foreign cells stick together
- Precipitation - Combines with antigen = insoluble
- Neutralisation - Binds to antigen to block receptors
- Lysis - kills antigen cell directly
- Opsonisation - Marks antigen for other immune cells
- Complementation Cascade - triggers co-ordinated immune response via enzymes for chemotaxis and supplementation
Define Infection and Infectious Disease
Infection - Complication of immune function
Infectious Disease - tissue destruction from micro-organism (due to successful micro-organism or weakened host)
Define the terms host, resident flora and pathogen
Host - individual that contracts the infection
Resident flora - micro-organisms that live on or within body but don’t cause harm
Pathogen - Disease producing micro-organisms
Describe the stages of acute infection
- Pathogen enters host (inflammation + immune responses triggered)
- Incubation period
- Prodrome (disease is present with no symptoms)
- Clinical illness
Leading to EITHER - Recovery (adequate immune response)
OR - Chronic infection (suboptimal immune defense)
- treatment required for recovery
OR - Overwhelming infection (inadequate immune defense)
- Septicemia
- Shock
- Death (if adequate treatment is not given in timely manner)
What are the clinical manifestations of infection
> Inflammatory/ immune responses - Pain/heat/swelling/redness/loss of function > Lymphadenopathy - raised lymph nodes > Purulent exudate - Puss > Malaise - feeling unwell > Weakness > Anorexia - loss of apetite > Headache > Nausea
Name the types of pathogens
- Bacteria
- Viruses
- Fungi
- Protozoa (moveable organisms)
- Rickettsiae (intracellular parasites)
- Helminths (worms)
- Mycoplasma (extracellular)
What tests can we do for infection
- White blood cell count (non-specific)
- Serum antibody levels (check history and specific antibodies present)
- Cultures - identify organism and where thrives/dies
Describe the Chain of Infection and how to break it
- Infectious agent (bacteria, virus etc.)
- break via sterilization - Reservoirs (people, equipment, water)
- break via sanitization and antimicrobial drugs - Portal of exit (excretion, skin, secretions etc.)
- break via hand washing, covering secretions, trash disposal - Transmission (contact, ingestion, airborne etc.)
- break via isolation, hand washing, sterilization, airflow control - Portal of entry (mucous membranes, GI tract etc.)
- break via covering entry points - Susceptible host (elderly, weakened immune etc.)
- break via Recognising high risk patients, treatment of underlying conditions to strengthen immune system
When should you wash your hands?
- Before patient contact
- Before aseptic task
- after body fluid exposure risk
- after patient contact
- after contact with patient surroundings
Define sepsis and septic shock
Sepsis
- life threatening organ dysfunction cause by dysregulated host response to infection
Septic shock
- Profound Circulatory, Cellular, Metabolic abnormalities (with greater risk of mortality) than sepsis alone
