Defense and disease Flashcards
Immunity?
Collective term for all organism’s defense mechanisms
Components of immune system and functions.
Bone marrow - Produce red blood cells
Thymus gland - aids maturation of T-lymphocytes
Lymph nodes - Contain macrophages and lymphocytes
Spleen - Filters debris from blood.
Features of innate immunity? (your default immune system)
non-specific from birth first line of defence rapid response - Activates acquired immune system through cell signalling.
Pathogen barriers?
Tears, mucus, sweat, fur
Examples of innate immunity?
Inflamatory response, fever
What do macrophages circulate in?
extracellular fluid
What are macrophages?
Antigen presenting cell for T cell to detect.
What happens to neutrofils?
Released to kill other bacteria in localised area.
Recall process of phagocytosis!
Yeah…thumbs up
What do natural killer cells do?
Target viral host cells
- Recognises cells that have lost surface glycoproteins - MHC-1.
- Create hole in infected cells plasma membrane.
- Water enters cell via osmosis and the cell bursts.
What cells do NK cells also target?
Cancerous cells.
What’s the inflammatory response?
Innate immune response used a lot in wild animals.
Process of a fever?
- Macrophage phagocytes a microbe and secretes intrleukin-1.
- Interleukin-1 travels in bloodstream to brain.
- Brain raises core body temperature in response - Fever.
What do antibodies do?
Bind to pathogens and self cells.
Recognise specific antigens they are complimentary to.
Antibody structure?
4 polypeptides - 2 light chains/ 2 heavy chains.
Antigen binding site is the variable region
variable and non variable regions
chains held together by disulphide bonds.
What can antibodies also be called
immunoglobins
Classes of antibodies?
IgB, IgE, IgD, IgM, IgA
Remember IgBEDMA
Features of Aquired immunity
- Specific
- Slow response
- Called adaptive immunity (not born with it).
Types of acquired immunity?
Active-Natural-Clinical disease (having disease), subclinical infection (Having infection).
Active-Artificial-Vaccine, toxoid.
Passive-Natural-From mother (inherited)
Passive-Artificial-immunoglobins (from vaccines)
Why are lymphocytes critical to specific immune response?
- Produced in bone marrow
- Circulate in blood and lymphatic system
- B lymphocytes/ T lymphocytes.
Process of T-cell mediated immunity?
- Macrophage presents complimentary viral antigen on its cell surface membrane via MHC-II protein.
- T helper cell has a receptor complimentary to viral antigen and so it takes viral antigen.
- At same time antigen -presenting cell uses MHC-I protein to provide viral antigen to cytotoxic T cell with a complimentary receptor.
- Proliferation - helper T cell gives interlukin-2 to cytotoxic T cell.
- Cytotoxic T-cell binds to an infected cell and destroys it as it’s complimentary.
Process of B-cell immunity?
- Invading microbes are binded to by B cell receptors (antibodies).
- At same time macrophage processes antigen from microbe by MHC-II protein and transfers antigen to complimentary T cell receptor on helper T cell.
- Helper T cell transfers processed antigen to complimentary receptor on a B cell.
- Clonal selection - B cell divides by mitosis into plasma cells that secrete monoclonal antibodies specific to original microbe.
- Antibodies bind to microbes and mark them as destructible.
- Same plasma cells divide into memory cells that record pathogen’s antigen for next time. So in future invasion it can divide into plasma cells with monoclonal antibodies specific to that pathogen.
What do vaccines do and why?
-Produces same effect as active immunity without true exposure to the real pathogen.
-Therefore the recipient of the vaccination does not become ill from the disease
.- Can provide life long protection via memory B cells.
What are the issues with vaccines?
Risky - Development expensive and not 100% successful
Needs a consumer market
Disease eradication badly effects business
Not a vaccine for every infectious disease.
Pathogens mutate and evolve - past vaccines stop working so need replacement.
How does herd immunity work?
- No one immune - Contagious disease spreads through population.
- Some population immunised - contagious disease spreads through some of population.
- Most of population immunised - spreads of contagious disease is contained.
How do Allergic reactions work?
- Allergen contacts B cell.
- Divides into plasma cell that release IgE antibodies.
- Mast cell has IgE receptors.
- Mast cells IgE receptors bind to allergens which triggers histomines to be released by Mast cell as an allergic reaction.
What’s the autoimmune response?
Body fails to detect self cell and attacks it.
Features of Immunodeficiency?
- Primary or secondary depending on if it occurs In infancy or birth.
- Disorders include protein deficiencies - HIV infection, removal of spleen.
