Immunity Flashcards
(30 cards)
Role of the macrophage?
phagocytic cell, hunt pathogens, also can release cytokines in order to signal to other cells in the area
What are mast cells?
Found in mucous membranes and connective tissue. when activated they release cytokines and granules to create an inflammatory cascade.
Role of natural killer cells?
Kill and destroy cells that are infected in order to stop the spread of pathogen
Role od dendritic cells?
are antigen presenting cells, acts as messengers for rest of immune system, Bridge between innate and adaptive
Name the physical barriers to pathogens?
skin is slightly acidic and has own flora, body hair, mucous , cillia, ph2 of stomach and alkaline intestine, bile, tears contain lysozyme, sweat, saliva
What are the general immune responses?
- inflammatory - actively brings immune cells both the site of an infection by increasing blood flow to the area
- complement - an immune response that marks pathogens for destruction and makes holes in the cells membrane
Difference between innate and adaptive immunity?
innate is general, non specific so anything determined as non self is a target. Activated by the presence of antigens and their chemical components. no lag phase, no memory
Adaptive relys on B and T cells and more specific to each antigen. Has a lag phase but has memory
How do cells sense pathogens?
Pathogen recognition receptors: PRRs
4main classes of PRRs?
NLRs
CLRs
TLRs
RLRs
What is a PAMP?
pathogen associated molecular pattern: specific to the microorganism and normally essential for pathogen viability. e.g.. flagellin, viral ssRNA and glycans
What are defensins?
produced by epithelial cells and phagocytes, bind to phospholipid bilayers and form pores, bury inside and lyse cell. are amphipathic
Lymphoid organs?
spleen, thymus, bone marrow and the lymph nodes
What ar the 4 steps of the complement system?
- foreign particles are marked for phagocytosis
- cytokines and chemokines attract macrophages
- Proteins destroy membrane causing it to lyse
- antibodies bind pathogens together - agglutination
What is the strucutre of antibodies?
4 proteins, 2 light and 2 heavy chains each has a variable region that is specific to antigens. Interacts with antigen at the FAB point - Fragment antigens binding point
Where do T and B cells derive from and mature?
both derive from bone marrow stem cells called hematopoitic
B mature in bone marrow
T mature in thymus
What do T cells do?
express recepotros CD4 and CD8 that bind to the receptor molecules MHC1 and MHC2 on the antigen presenting cells. Activate the T cells to differentiate into =
T helper - express CD4 and activate cytoxic T cells and B cells
T regulatory - express CD4 and CD25, distinguish between self and foreign to eliminate autoimmune
Cytotoxic T cells - express CD8 remove pathogens and infected hosts
When does inflammation occur?
following, necrosis, trauma, infection, allergy, extreme temperature and foreign body
Signals of inflammation?
calor, red, hotness, pain, swelling, loss of function
What is acute inflammation?
has a short duration and neutrophils are main response.
Result of damage of infection that affects vasculature
Steps of acute inflammation?
- diameter of blood vessel increases
- Increase in permeability of blood vessels due to histamine so increase fluid influx into tissue
- Swelling - oedema
- reduction in blood velocity caused by vasodilation promoting immune cells to enter tissue
What is chronic inflammation?
mainly involves plasma cells, lymphocytes and macrophages.
Can b result of acute inflammation,arthritis, abscesses
Poor vasculation of the bones means poor recovery
Steps of chronic inflammation?
tissue destruction, granulation of the wound, fibrosis - proliferation of undifferentiated fibroblasts.
Parcelling off of damaged tissue that cannot be prepared. Fibrous casing around infected areas
What is necrosis?
is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Causes cells around it to die too. Requires an external signal e.g. cuts or toxins or burns
What is frostbite?
The freezing of the cytosol of cells, it expands and causes rupture of plasma membrane
