Unit 4 AOS 1 Key Terms Flashcards
Define adaptive immune response
An immune response directed against a specific antigen; it retains memory of that antigen so that, on subsequent exposure to the same antigen, it responds with a secondary response
Define allergen
An antigen that is normally innocuous but can sometimes cause an over-reaction from the immune system known as an allergy
Define allergy
An immune response characterised by IgE production to an innocuous substance
Define anaphylactic shock
A severe allergic reaction that causes widespread swelling, including of the face and neck, which can lead to difficulty breathing and a life-threatening reaction
Define antibiotic
A naturally or synthetically produced compound that is toxic to bacteria
Define antigen
A large molecule, usually a protein or polysaccharide, that generates an immune response
Define apoptosis
A programmed series of events that lead to cell death as a result of dismantling of the internal contents of the cells by various enzymes, including capases
Define bacteria
Unnicellular prokaryotes that can be pathogenic and therefore carry diesease
Define bacterial capsule
A polysaccharide layer surrounding some bacteria that makes them resistant to phagocytosis and thus more virulent
Define cellular pathogen
A disease-causing pathogen that is made up of one or more living cells such as bacteria or fungi
Define chemokine
A type of cytokine that induces chemotaxis
Define chemotaxis
The movement of an organism or a cell along a chemical concentration gradient either towards or away from a cytokine
Define cilia
Slender hair-like structures projecting from a cell surface that beat against fluid
Define companion plant
A plant that is grown with another plant because one species improves the growth of another
Define complement
A number of small proteins found the blood that, when activated, promote chemotaxis, cell lysis and phagocytosis
Define cytokine
A signalling molecule that coordinates inflammation and immune responses and that leukocytes use to communicate with one another; includes interleukins and interferons
Define defensin
A type of small antimicrobial peptide secreted by nearly all plants and animals
Define degranulation
A cellular process in which the granules of neutrophils, mast cells, basophils or eosinophils are emptied into extracellular surroundings
Define dendritic cell
A phagocyte with membranous extensions that engulf pathogens, process them and present them to other cells of the immune system
Define desensitisation
A treatment to make a person more tolerant to a substance to which they are allergic
Define disease
Any condition that interferes with how an organism, or any part of it, funtions
Define eosinophil
A leukocyte that secretes powerful enzymes capable of rupturing multicellular organisms
Define first line of defence
Physical and chemical barriers that keep pathogens from entering the body of a living thing
Define flagellum
A helical filament that rotates to give bacteria locomotion
Define fungi
A heterophobic organism made up of one or many cells; has cell walls but is not a plant
Define granulocyte
A white blood cell that has granules in the cytoplasm
Define histamine
A chemical released by mast cells and basophils that increases blood flow and the permeability of capillaries
Define host
THe organism in which a parasite lives
Define immune system
A complex network of cells, tissues and organs in the body that detect differences between self-molecules and foreign (non-self) organisms, and mounts an immune response that results in the formation of memory lymphocytes
Define immune tolerance
Tolerance of the presence of an antigen by the immune system so it does not mount an immune response to the antigen
Define infectious disease
A disorder caused by bacteria, viruses, fungi and other organisms, that can often be transmitted to other members of a population
Define inflammation
An innate response to infection or damage that causes pain, swelling, heat and redness
Define innate immune response
A response to a pathogen that is not specific to the antigen, only that it has been identified as being non-self; the response does not generate antibodies memory lymphocytes
Define interferon
A type of cytokine produced by the cells of the immune system in response to challenges by foreign agents such as viruses, bacteria, parasites and tumour cells
Define keratin
The tough, fibrous protein of the outer epidermis layer
Define leukocyte
The general term for white blood cell
Define lymphocyte
A type of leukocyte involved in adaptive immune system
Define lysis
The process of cell bursting
Define lysozyme
An antibacterial enzyme found in tears, saliva and other body fluids
Define macrophage
A large white blood cell that phagocytoses pathogens, originates as monocytes in circulation
Define mast cell
A cell that is located in the tissues and releases granules containing histamines when activated
Define microbiome
The bateria, viruses and fungi that live in the gut plus their released metabolites and nucleic acids that exist in a specific environment
Define microbiota
A community of micro-organisms, including fungi and bacteria, that live in or on another organism
Define microflora
A community of micro-organisms, including fungi and bacteria, that live in or on another organism
Define monocyte
A white blood cell that circulates in the blood and matures into a macrophage when it moves from the blood into the tissues
Define mucous membrane
A mucus-secreting membrane that lines the respiratory, excretory and reproductive tracts
Define natural killer cell
A circulating leukocyte that kills body cells infected with a virus or transformed by cancer
Define necrosis
Cell death that results from tissue damage or infection when the plasma membrane is breached; results in inflammation
Define neutrophil
A phagocytic leukocyte found in the blood and tissues
Define non-ceullular pathogen
A disease-causing pathogen that is not made of living cells; for example, viruses and prions
Define non-self antigen
A molecule that is not recognised by the immune system as being part of the organism itself
Define non-specific response
A resonse that is the same regardless of the type of antigen
Define obligate parasite
A parasite that cannot complete its life cycle without a suitable host; without a host, the parasite cannot reproduce
Define opsonisation
The process in which a pathogen is coated with antibodies and/or complement and marked for phagocytosis
Define pathogen
An organism foreign to the body and capable of causing disease
Define phagocyte
A cell that is capable of phagocytosis; includes macrrophages, dendritic cells and neutrophils
Define phagocytosis
A process by which phagocytes engulf a particle or cell
Define phagolysosome
A membrne-bound vesicle formed from the fusion of a phagosome and a lysosome
Define phagosome
A membrane-bound vesicle formed around a particle during phagocytosis
Define platelet
A cell fragment found in the blood involved in blood clotting
Define prion
An infectious protein that can cause other unaffected prion proteins in the brain to take the affected form, causing transmissable spongiform encephalopathesis
Define protist
A unicellular eukaryotic organism
Define second line of defence
non-specific immune responses including fever and inflammation
Define secondary metabolite
An organic compound produced by bacteria, fungi or plants; its role is to sustainfunctional and homeostatic health of cells withing organs by assistingcells to excrete waste and toxic substances
Define self-antigen
An antigen or a molecule that is a normal body component
Define sensitisation
Initial exposure to an allergen resulting in an adaptive immune response that generates IgE
Define sterile inflammation
Inflammation resulting from the detection of damage - or danger-associated molecular patterns released during tissue injury in the absence of infection
Define transmitted
When an infection is passed from one person or organism to another
Define vasodilation
Widening of blood vessels, particularly arterioles
Define virus
An obligate intracellular pathogen that can use the host cell’s machinery to replicate itself; usually consists of a nucleic acid surrounded by a protein coat
Define active immunity
WHe, after vaccination, memory cells are created that provide immunity against further exposure to antigens
Define agglutination
When antigens or pathogens become stuck together because of antibody binding
Define antibody
A Y-shaped protein that binds to foreign substances that invade the body; also called immunoglobulin
Define antigen-presenting cell (APC)
A cell that displays peptides derived from processed antigens on major histocompatability complex class II molecules for presentation to Tₕ cells; can be B cells, macrophages and dendritic cells
Define autoimmune disease
A disease caused we a person’s immune system mistakens self-cells and tissues as non-self and initiates an immune response against them
Define B cell
A class of lymphocyte that, once activated, produces antibodies; also called a B lymphocyte
Define B cell receptor
A surface-bound antibody that serves as a receptor so that B cells can detect antigens
Define B plasma cell
A cell that originates in the bone marrow and produces large quantities of antibodies
Define bone marrow
Soft tissue found inside some bones that contains stem cels that produce cells of the immune system
Define cell-mediated immunity
An immune response initiated by cells, which does not involve antibodies
Define clonal selection
The process in which lymphocytes that have bound to an antigen divide rapidly and become more numerous than other clones
Define cytotoxic T cell (T꜀ cell)
A class of lymphocyte thst destroys virally infected or cancerous cells by secreting proteins that result in the extrinsic pathway of apoptosis, also called a cytotoxic T lumphocyte
Define epitope
A small part of a larger molecule that binds to a receptor site such as B cell receptors and T cell receptors
Define helper T cell (Tₕ cell)
A lymphocyte that assists cytotoxic T cells, B cells and macrophages by secreting cytokines and providing contact-dependent signalling; also called a helper T lymphocyte
Define humoral immune response
An adaptive immune response mediated by antibodies
Define immune
Having resistance to infection by a specific pathogen
Define immunoglobulin (Ig)
A Y-shaped protein produced by plasma cells that bind to a specific antigen; also called antibody
Define interleukin
A subset of cytokines that assists with the coordination of cells involved in the immune response
Define interstitial fluid
A fluid that lies between cells; also known as tissue fluid or extracellular fluid
Define lymph
A colourless fluid that originates from tissue fluid
Deifne lymph node
An immunological organ in which antigens are trapped or delivered by phagocytes to present to lymphocytes and initiate an adaptive immune response
Define lymphatic system
A system of organs (thymus, bone marrow, spleen, lymph nodes, network of vessels) and lymph fluid that are involved in transporting lymphocytes and removing foreign matter
Define major histocompatability complex (MHC)
Protein markers found on cell surfaces that are important in distinguising self from non-self; MHC class I is found onall cells and MHC class II is found only on antigen-presenting cells
Define memory cell
A long-lived lymphocyte capable of responding to a particular antigen when it is reintroduced; made from B cells and T cells
Define MHC restriction
Refers to the fact that T cells can only recognise antigens that are presented on MHC proteins
Define mucosal-associated lymphoid tissue (MALT)
An extensive system of lymphoid tissue deposited all over the body; initiates immune responses along mucosal areas such as gastrointestinal tract, eyes and lungs
Define neutralisation
The process by which antibodies prevent toxins from acting by binding to them and blocking them from binding to their targets
Define passive immunity
Immunity characterised by the transfer of antibodies from one individual to antoher; does not generate immunological memory
Define primary lymphoid organ
The bone marrow and thymus; responsibe for the production and maturation of immune cells
Define primary response
The response generated when an antigen is encountered for the first time; contrasted with the secondary response
Define regulatory T cell (Tᵣₑ₉ cell)
A class of lymphocyte that helps to negatively regulate the immune response; also called a regulatory T lymphocyte
Define secondary lymphoid organ
An organ that provides anenvironment for the initiation of the immune repsonse; includes lymph nodes, spleen and mucous-associated lymphoid tissue
Define secondary response
The response generated when the body encounters a pathogen to which it has previously generated an immune response; involves reactivation of memory lymphocytes and occurs more rapidly and with greater magnitude than the primary response
Define self-tolerance
The deletion or inactivation of ymphocyte clones that can bind to self-antigens to prevent an immune response to these antigens
Define specific response
An adaptive immune response directed against a particular antigen that retains immunological memory og that antigen
Define spleen
An abdominal organ that stores white blood cells
Define T cell receptor
A protein receptor found on the surface of T ceels, binds to antigens presented on major histocompatability complex proteins
Define thymus
The glands in the upper chest where T cells mature
Define autoantibody
An antibody produced by a person’s immune system that is directed against the person’s own proteins
Define autoimmune disease
A disease caused when a person’s immune system mistakes slef-cells and tissues as non-self and initiates an immune response against them
Define cancer
uncontrolled abnormal division of cells that are not kept in check by the immune system and invade other areas of the body
Define carrier
A person who does not show symptoms of a disease but can transmit the infection to others
Define endemic
Restriced or native to a certain locality
Define epidemic
The rapid spread of a disease across a number of countires
Define herd immunity
WHen unvaccinated individuals are protected against a disease because a large number of people (between 60-95% depending on the disease) have been vacinated, thereby making it unlikely that unvaccinated people wil come into contact with anyone suffering from the disease
Define hybridoma
A cell involved in the production of large amounts of monoclonal antibodies
Define immunisation
The process of making a person immune to a disease through vaccination
Define immunotherapy
Boosting the ability of a person’s own immune system to fight cancer
Define infectivity
The ability of a pathogen to spread from one host to another host
Define Koch’s postulates
A set of criteria to determine the causative agent of a disease
Define latent
Not active
Define monoclonal antibody
A laboratory-produced molecule that serves as a substitute antibody to fight cancerous cells
Define pandemic
The spread of a disease across the world
Define primary host
An organism in which a pathogen reproduces
Define quarantine
Restricting the mobility of a person or persons to a certain area so they reduce contact with other people in order to stop the spread of a pathogen
Define secondary host
An organism om which the immature pathogen becomes mature
Define sporadic
Seen infrequently in a small number of people
Define T-cell transfer therapy
A therapy that boosts the ability of T cells to fight cancer cells
Define tumour
A mass of abnormally growing cells
Define vaccination
The administration of a vaccine to protect someone from a disease
Define virulence
The capacity of a pathogen to cause severe disease within its host
Define zoonotic
Describes a disease that can be transmitted from animals to humans
