6.3 Flashcards
define antigens
glycoproteins, proteins or carbohydrates on the surface of cells which are recognized by white blood cells and stimulate the production of antibodies
what are non-specific responses
triggered by body cells breaking down and releasing chemicals
define inflammation
a non-specific response to infection involving the release of histamines from mast cells and basophils causing vasodilation, increasing temperature of localised areas and increases permeability of capillary wall
what are mast cells
do not circulate in the blood stream they reside in the skin and muscular tissue
become activated when they come in contact with foreign antigens
release histamines from granules
state 3 physical barriers to pathogens
skin consisting of keratin
stomach acid
gut skin & flora - natural bacteria which competes with pathogens
state the 3 granulocytes
neutrophils
eosinophil
basophil
state the 2 main agranulocytes and their sub cells
lymphocytes - B lymphocyte, T lymphocyte, natural killer cell
Monocyte
what causes a fever and why is it effective
hypothalamus sets body temperature higher
decreases speed of pathogen reproduction
increases rate of specific immune response
what is lysosome action and why is it effective
lysosome is an enzyme found in secretions such as tears and mucus
kills bacteria by damaging their cell wall
what is phagocytosis
white blood cells engulf pathogens and destroy them by fusing a pathogen enclosed in a phagocytic vesicle
what are basophils
produce histamines
circulate in bloodstream
bean shaped nucleus
not phagocytic
what are eosinophils
lobed nucleus allows it to morph shape in order to engulf pathogens
produce chemicals which counteract inflammatory histamines
what are natural killer cells
type of leukocyte that can recognize cells that are infected
release proteins that educe apotosis by perforating the membrane
control infection until adaptive immune system is activated
define specific immune response
specific response of the immune system to specific pathogens, each T cell and B cell is tailored towards a specific pathogen and is not effective against any others
what are the 4 key features of specific immunity
distinguish self from non-self
specific to each foreign cell
diverse
immunological memory
define humoral response
the immune response to pathogens free in the tissues and bloodstream
what is cell mediated response
the response to your own body cells that have altered self antigen
what is the major histocompatibility complex (MHC)
a molecule found on the cell surface membrane of all cells and is used to present antigens, both self and non-self
what are B cells
made and matured in the bone marrow
circulate in the bloodstream and are concentrated in the lymph glands
produce immunoglobulin proteins - antibodies that target specific pathogens
what is antibody opsonization
a process by which a pathogen is marked for phagocytosis
what is aggulation
when foreign particles are clumped together via antibodies
what is neutralization
when antibodies bind to an inactive virus and toxins
what is B cell activation (T cell independent)
B cell and its membrane-bound antibodies recognize and attach to antigens and B cells become activated
what are the 3 types of B cells
B effector cells
B plasma cells
B memory cells
what are the 3 types of T cells
T killer cells
T helper cells
T memory cells
whats the role of killer T cells
produce chemicals to destroy infected body cells by causing lysis
whats the role of helper T cells
activate the plasma cells and secrete opsonin’s which label the pathogen for phagocytosis
whats the role of memory T cells
long lived cells that make up part of immunological memory
what are B effector cells
divide to form plasma cell clones
what are (B) plasma cells
produce antibodies for a particular antigen
what are B memory cells
provide immunological memory to specific antigens
what is an APC
antigen presenting cell which display antigens on the cell surface membrane
what is B cell activation (T cell dependent)
an activated T helper cell with complementary receptor binds to the APC and produces cytokines that stimulate B cells
how are T cells activated
binding of the T cell to an APC triggers cloning of T cells into T memory and T helper cells
what is clonal selection
the selection of the cells that carry the right antibody for a specific antigen
why do (B) plasma cells have lots of ribosomes and an extensive endoplasmic reticulum
for the production of large quantities of protein antibodies
what is cell-mediated response
bacteria infects a host cell
host cell presents the antigens on its cell surface membrane and becomes an APC
T helper cells with complementary receptors bind to the APC
cytokines are released from the T helper cell which stimulates the production of T memory cells and active T killer cells
the active T killer cell binds to the APC and releases perforin which causes lysis of infected cells
what are the 2 types of white blood cells involved in phagocytosis
neutrophils
macrophages
how does phagocytosis destroy pathogens
phagocyte engulfs pathogen via endocytosis to form a phagosome and fuses with lysosome
the lysosomes digest the pathogen and leaves the antigens
the antigen markers and then presented on the cell surface membrane via to MHC
how do APCs present antigens to T cells
antigens are presented on the cell surface membrane via the MHC
these then bind to the CD4 receptors on the T helper cell
what are the stages of clonal selection
antigen binds to B cell with complementary receptors and engulfs the bacteria via endocytosis
enzymes break down the bacteria and leaves the antigens
B cell becomes an APC
an activated T helper cell with a complementary receptor binds to the APC and produces cytokines which stimulate the B cell
B cell divides to give B memory and B effector cells
what does perforin do
causes lysis of cells
what is the primary immune response
production of antibodies by B plasma cells from B effector cells and T killer cell activation
what is the secondary immune response
faster long lasting immune response due to the presence of B and T memory cells which are able to respond very rapidly
what is natural active immunity
when the body produces its own antibodies to an antigen encountered naturally
what is natural passive immunity
when antibodies made by the mother are passed to the baby via the placenta or breast milk
what is immunisation
the process of protecting people from infection by giving them active or passive artificial immunity
define vaccination
the introduction of a harmless forms of pathogens or antigens by injection or mouth to produce artificial immunity
what makes immunity passive
when your body does not make the antibodies itself
what is artificial passive immunity
when antibodies are extracted from one individual and injected into another
what is artificial active immunity
when the body produces it’s own antibodies to an antigen acquired through a vaccination
what is an attenuated pathogen
viable pathogens that have been modified so that they do not cause disease but still cause an immune response that results in the production of antibodies and immunity
what is herd immunity
when a high proportion of a population is immune to a pathogen (usually by vaccination) therefor lower the risk of infection to all even those without immunity
how do vaccinations work
an attenuated pathogen is introduced to the blood usually by injection which causes an immune response and leave memory cells in the blood therefor exposure to that specific pathogen does not result in disease as the immune response is a lot faster and more vigorous
why is eradication of a disease often not possible through vaccination
there are many pathogens that survive in soil, water or animal hosts
what is the difference between elimination and eradication of a disease
elimination - the disease disappears but remains present in the environment
eradication - the disease is no longer found anywhere
what are the advantages of vaccinations
- the person is protected against a disease which could potentially kill them
- herd immunity protects those that can’t be vaccinated
- save money on treating diseases
what are the disadvantages of vaccinations
- some people can be allergic to the vaccination
- extreme immune responses could cause the person to be extremely ill when getting the vaccine
- widespread vaccinations may be linked to an increase in allergies and asthma
- may not benefit the individual but is done for all of society
give 2 differences between specific and non-specific immune response
non-specific - involves inflammation & phagocytosis
immediate
specific - has a lag time
is complementary to the pathogen
what are the 2 specific immune responses
cell-mediated
humoral
what is the humoral response
complementary T helper cells bind to antigens on APCs via the CD4 which stimulates the release of cytokines that then cause clonal expansion of complementary B effector cells which then divide to form plasma cells
the plasma cells secrete antibodies complementary to the pathogens antigens
