immune system Flashcards
what should you consider about the immune system
the immune system performs 2 vital functions that are critical for the maintenance of homeostasis
what are the 2 functions of the immune system
a) inducing an effective and safe response against foreign antigens
b) avoiding a response to components of self antigens by enforcing stringent regulatory controls over dangerous self reactive cells that are capable of mounting devastating immune attacks on self tissues
antigen
antigens are substances that can mobilize the immune system, leading to an immune response. most often antigens are large molecules that are not normally present in the body and they are the ultimate target of the immune system
antibody
antibodies are also called immunoglobulins and are soluble proteins secreted by activated b cells or plasma cells in response to exposure to an antigen. antibodies are also capable of binding with high specificity to that antigen
what are the 2 categories of antigens?
a) infectious/microbial antigens includes bacteria, virak, protozoal and helminths
b) noninfectious antigens which includes self antigens, food antigens, plant products, dust, cell surface proteins, synthetic chemicals, venoms and insect toxins
what 2 things should you consider about antigens
epitopes are antigenic determinants and antigens are a component of cell walls and or plasma membranes and have one ore more epitopes
what are the 2 categories of immunity
innate immune system and adaptive immune system
what 3 things should you consider about innate immune system
a) it is rapid and non specific
b) is present at birth
c) uses physical, chemical and cellular components
what 4 things should you consider about adaptive immune system
a) slower to respond
b) targets specific organisms
c) develops and adapts as animal matures
d) uses antibodies, memory cells, plasma cells and B/T lymphocytes
what 4 things should you consider about non specific defense mechanisms
a) species resistance
b) mechanical and chemical barriers
c) inflammatory response such as phagocytic cellular defense
d) complement and cytokines
what should you consider about species resistance
it is a natural immunity meaning that not all diseases have the ability to affect all animals
what are the 5 mechanical/chemical barriers?
skin/cilia mucous membranes mucus sebum enzymes
explain the 1st, 2nd and 3rd line of defenses
- once a microorganism has invaded the 1st line of defense kicks in and is the external innate immunity and physical barriers including the skin, self cleaning and normal flora
- if the 1st line of defense doesn’t stop the invasion then the 2nd line of defense kicks in which is the internal innate immunity including inflammation lysozyme
- if both fail to stop invasion then the 3rd lines of defense which is the adaptive immunity including cell-antibody production/cell mediated immunity
what are the 5 pathways of acute inflammation and generation
a) infection and trauma lead to tissue damage which could then lead to nerve damage resulting in pain
b) infection and trauma leads to tissue damage which results in vasoactive molecules causing pain
c) infection and trauma leads to tissue damage which creates vasoactive molecules leading to increased blood flow causing redness and heat
d) infection and trauma leads to tissue damage which creates vasoactive molecules leading to increased vascular permeability causing swelling
e) infection and trauma leads to tissue damage which creates chemotactic molecules resulting in neutrophil emigration causing swelling
what 2 things should you consider about phagocytic cellular defense
myeloid which includes neutrophils, basophils and eosinophils and macrophage including monocytes and macrophages
what 3 things should you consider about neutrophils
a) are considered the 1st responder cells to combat invading antigens
b) they respond rapidly and can readily phagocytize the antigen
c) what they cannot do is present antigens to lymphocytes
what should you consider about macrophages and monocytes
macrophages are attracted to bacterial products and by the chemotactic factors released from damaged tissues. they are long lived, secrete cytokines and chemokines can present antigens to immune system and are found in tissues where entry of antigen is likely
what 3 things should you consider about complement in plasma
a) plasma proteins mostly inactive enzymes
b) activated by the presence of an antigen
c) trigger inflammation and alter microbial membranes
why is the complement system a key component of innate immunity
complement may either alter microbial membranes or trigger inflammation, either way it hastens the elimination of microbial invaders
what 4 things should you consider about cytokines
a) communicators, signaling proteins
b) interleukins, interferons, chemokines
c) they mediate the immune and inflammatory response attracting immune cells to a specific site of infection, inflammation or trauma
d) interleukins control leukocytes growth, differentiation and activation during an immune response
what are the 7 origins and biological activities of interleukin
a) promotes inflammation enhancing collagen synthesis, chondrocyte activity, fibroblast activity, and bone resorption
b) kills cells, specifically tumor cells
c) affects leukocytes enhancing the TH2 cell cytokine production, eosinophil degranulation and basophil degranulation
d) affects the brain inducing fever, drowsiness, and loss of appetite
e) affects metabolism enhancing mucous production, lipoprotein lipase, acute phase protein synthesis and mobilizes amino acids
f) affects blood flow enhancing IFN synthesis and integrin expression
g) affects cell growth by enhancing the growth of fibroblasts, keratinocytes, messengial cells, glial cells and vascular smooth muscle
what should you consider about interferons
they are proteins produced by an animals immune system interferes with the ability of viruses to cause disease by preventing the replication within the host cell
what should you consider about chemokines
they are chemotactic cytokines that stimulate the movement of leukocytes from blood into tissue and toward an injury/inflammatory site
what should you consider about NK cells
they are found in blood and lymph, identify and kill virus infected cells, stressed cells and tumor cells and does not cause lysis
what are the 3 key features of innate immunity?
a) rapid response against invading pathogens
b) nonspecific
c) physical, chemical and cellular barriers
what are the 2 types pf specific/acquired immunity
a) cell mediated by T cells
b) humoral immunity by B cells
what should you consider about specific/acquired immunity
it is long lasting involving T and B lymphocytes, APCs although part of innate immune system play a central role in activating lymphocytes
what should you consider about T cells
t cells are activated lymphocytes that secrete cytokines that are essential for defense against intracellular pathogens, activation of other cells and coordination of immune responses
what should you consider about B cells
B lymphocytes have 2 functions: secreting antibodies that bind specifically to that antigen that induced the antibody response and memory cells for future exposure
what should you consider bout cell mediated immunity
it has tightly regulated development, and maturation resulting in T-helper cells, Killer T cells and regulatory
what should you consider about humoral immunity
the exposure of an animal to a foreign antigen usually elicits a specific immune response and may involve specifically reactive T-cells or and/or antibodies able to bind specifically with the foreign antigen
what is a lag period
this is typically when an animal is exposed to a particular foreign antigen for the 1st time, no antibodies specific for that antigen will be detected in blood or secretion for several days
what 3 things should you consider about antibodies
a) renders the antigen harmless to the body
b) causes antigens to agglutinate and be removed from solution
c) destruction of antigenic cells
what are the 4 antibodies
IgM, IgG, IgA, IgE
what should you consider about IgM
they are predominant ab in 1st exposure, then disappear, they are large and therefore usually only found in blood and is the 1st Ig made by newborns
what should you consider about IgG
they are the smallest but most common , found in blood, tissues, and lymph/colostrum crosses placenta are made during 1st exposure and has a slow production
what should you consider about IgA
in secretions therefore important for antigens entering through mucosal surfaces and blocks penetration of antigen into body
what should you consider about IgE
they are bound to mast cells, defense against environment and involved in allergic reactions
what is mucosal immunity
the immunity that happens on a cellular level but at a localized location
what is the difference between inherited and acquired immunity
inherited immunity affects the fetus before birth while acquired immunity is either natural or artificial and can be passive or active
why do diseases occur
they occur when specific and non specific immunity work to eliminate foreign substances from the body , essentially meaning the system fails
