immunology Flashcards
what are the 6 types of microbes?
bacteria
fungi
virus
protozoa
helminths
prions
what are the 4 stages a pathogen has to cause disease?
exposure
adhesion
invasion
infection
give 4 examples of direct transmission
direct contact, tissues, aerosol, indigestion
give 2 examples of indirect transmission
vector, enviroment
what is a prion?
a misfolded protein
what does a prion do?
gets inside cells and makes a copy of itself, then can duplicate so much it burts infected cells, causing it to spread
what are some barriers to infection?
skin, tears, discharge, wax, hair, acid
what is an antigen?
a substance recognised by the immune systems self or non-self and initiates a response
what is an antibody?
a blood protein produced in response to, and counteracting, a specific antigen
what are the 3 cells involved in phagocytosis?
dendritic cell
neutrophil cell
macrophage cell
what is the process of phagocytosis?
1) phagocyte collides with pathogen and recognises a foreign antigen.
2) cytoplasm engulfs pathogen.
3) pathogen is now in the phagocytic vacuole and lysosomes are introduced.
4) lysosomes digest virus with enzymes which break down the pathogen.
5) phagocytes present pathogen on surface to warn other immune cells.
what is inflammation?
localised response to injury or infection characterised by swelling or redness.
damaged cells release histamine which signals the release of cytokines
what do histamines do?
increase blood flow
make capillaries leakier
allow phagocytes to leave blood and enter tissues
what do cytokines do?
Cytokines are small proteins that are crucial in controlling the growth and activity of other immune system cells and blood cells.
Cytokines affect the growth of all blood cells and other cells that help the body’s immune and inflammation responses
what is innate immunity?
the first line of defense against invading pathogens
eg, phagocytes
what is adaptive immunity?
involves specialized immune cells and antibodies that attack and destroy foreign invaders and are able to prevent disease in the future by remembering what those substances look like
what are 2 types of lymphocytes?
T-cells = mature in the thymus gland
B-cells = mature in the bone marrow
what is cell mediated immunity?
T-cells response to a foreign antigen.
Receptors then bind to the antigens.
Mitosis happens and can be changed into 3 specilased cells (memory, cytotoxic, helper)
what is antibody mediated immunity?
helper t-cells stimulate b-cells to stimulate this reponse which involves antibodies.
antibodies bind to the antigens
what are 3 ways cell mediated immunity protects the body?
1) activates killer t-cells which kill infected cells
2) activates phagocytosis
3) helps b-cells in the humoral response
give 2 ways antibodies work
1) they can induce phagocytosis
2) cause agglutination of the pathogen
what are memory cells?
can be t or b cells stores in the lymph nodes.
specific to particular antigen
reactivated when body is attacked
how do antibodies inactivate pathogens?
1) neutralisation
2) phagocytosis
3) aggulation
what is a vaccine?
weakened form of a pathogen
what is passive immunity?
short term resulting from introduction of antibodies from another person eg, breastmilk
what is active immunity?
longer term resulting from person making own antibodies in response to specific antigen
what is a pathogen?
an organism causing disease to its host
what is immune response?
how an organism responds after being infected with a pathogen
what is a monoclonal antibody?
a specific, single type of antibody which are identical as produced by one type of immune cell
what is cell signalling?
process that cells communicate with each other.
release chemicals such as histamine and cytokines
what are phagocytes?
a cell that can engulf and absorb bacteria
what is phagocytosis?
the process of a phagocyte engulfing a pathogen or other foreign material
what are lymphocytes?
small white blood cells (b and t cells)
what does the activation of T cells lead to?
can activate from memory and release cytokines
what does the activation of B-cells lead to?
antibody-mediated response
activated b-cells produce antibodies
antibodies bind to and neutralise the antigens on pathogen
activated b-cells from memory
