AOS 4 unit 1 - pathogens glossary Flashcards
pathogens
an agent that causes disease
antigen
any molecule that may trigger an immune response
non-self antigen
a molecule from outside the body that is recognised by the immune system and initiates awn immune response - foreign antigen
Major Histocompatibility Complex (MHC) proteins
a group of proteins present on the surface of all the cells that enables the immune system to distinguish it as non self material
auto immune disease
a disease in which an individual’s immune system initiates an immune response against their own cells
allergen
a non-pathogenic antigen that triggers an allergic reaction
allergic reaction
an overreaction of the immune system to a non- pathogenic antigen
cellular pathogen
a pathogen that has a cellular structure and exhibits the processes of a living organism. Examples include
- bacteria,
- fungi,
- protozoa,
- parasites
non-cellular pathogen
a pathogen that neither has a cellular structure nor exhibits the processes of a living organism. Examples include viruses and prions
lysis
the disintegration or rupturing of a cell
Bacteria
Unicellular prokaryotes that can infect almost any part of the body. Bacteria can cause disease through the production of toxins and enzymes which either affect the functioning of cells or cause their death.
fungi
Eukaryotic organisms that include yeasts and moulds and contain long, branching filaments called hyphae.
worms
Multicellular invertebrate parasites whose development include egg, larval, and adult stages. Can vary in length, with the longest worms being over 55 m in length.
protozoa
Single-celled eukaryotes that can be free-living or parasitic. Protozoa have many different mechanisms of action – for example, some can inhibit nucleic acid synthesis, protein synthesis, and various stages of cellular respiration.
viruses
An infectious agent composed of genetic material (DNA or RNA) inside a protein coat (capsid). In some instances the protein coat is surrounded by a lipid envelope. Viruses are not able to independently reproduce, instead they insert their genetic material into a host’s cell and use the cell to replicate.
Viruses can cause disease through the lysis of cells during viral replication, the formation of cancer by affecting gene expression, and the over-stimulation of the immune system leading to organ damage.
prions
Abnormally folded proteins that have the ability to induce normal proteins nearby
to become misfolded. They only occur in mammals and affect only the brain and other neural structures. They are currently the only known infectious agents that don’t contain nucleic acids.
Agglutination
the clumping of particles together. in the immune system, antibodies can help clump pathogens together
antibody
a protein produced by plasma cells during the adaptive immune response that is specific to an antigen and combats pathogens in a variety of ways (immunoglobulin)
antigen-antibody complex
a structure formed by the complimentary binding between antigen and antibody molecules
b- lymphocytes
a type of lymphocyte that plays an important role in humeral immunity and differentiates into plasma cells and B memory cells
Cell-mediated immunity
an adaptive immune response in which infected or abnormal cells are destroyed by cytotoxic T cells, also known as t cell immunity
Clonal expansion
the process in which many copies of a lymphocyte are generated
Clonal selection
the process in which B and T cells encounter an antigen that matches their antigen-binding site, then generate many copies of themselves
Chemical barrier
a component of the first line if defence that features the use of enzymes, toxins and acids to protect against pathogen invasion
Complement protein
a number of different types of proteins found in the blood that opsonise
Complement protein
a number of different types of proteins found in the blood that opsonise, cause lysis, and attract phagocytes to invading pathogens
Cuticle
a waxy protective film covering the surface of a plant leaf
cytokine
a signalling molecule released by cells (typically in the immune system) which aids in communication between immune cells and helps protect against pathogens
Cytotoxic T lymphocyte (Tc Cell)
a differentiated T lymphocyte that is responsible fir the destruction of infected or abnormal cells
Dendritic cell
a type of leukocyte that engages in phagocytosis and antigen presentation
Degranulation
the release of granule contents from a cell
Eosinophil
a large granular leukocyte responsible for the release of toxic chemical mediators
Gall
an abnormal outgrowth of tissue in plants designed to limit the spread of an invading pathogen
Histamine
a molecule released bye mast cells that plays a key role in inflammation
Humoral immunity
an adaptive immune response in which extracellular pathogens are targeted by specific antibodies produced by plasma cells. also know as B cell immunity
Inflammation
a series of biochemical events that occur in the body against pathogens and foreign material. also known as white blood cells
Innate immune response
a component of the immune system that is composed of generalised and non-specific defences and/or responses to pathogens also known as non-specific
Interferon
a cytokine release by virally infected cells that increase the viral resistance of neighbouring uninfected cells
Leukocyte
a group of blood cells responsible for protecting the body against pathogens and foreign material. also known as white blood cells
Lymph node
a small secondary lymphoid tissue found throughout the body where antigen presenting cells activate the adaptive immune response
Lymphatic system
a large network of of vessels and tissues throughout the body that form an important component of both the circulatory and immune system
Macrophage
a type of leukocyte found throughout the body that engages in phagocytosis and antigen presentation
Mast cell
a type of leukocyte responsible for releasing histamine during allergic and inflammatory responses
Membrane attack complex
a pore formed by compliment proteins in the cell membrane of a pathogen, disrupting the membrane and leading to the pathogen destruction
Microbiological barrier
a component of the first line of defence in which the presence of normal flora limits the growth of pathogenic bacteria
Natural Killer cell
a type of leukocyte responsible for the recognition and destruction of damaged and/or infected host cells
Neutrophil
the most common type of leukocyte in the body. engages in phagocytosis of pathogens and foreign material as well as the release of cytokines
opsonisation
the mechanism by which compliment proteins attach to the surface of pathogens making them easier to phagocytose
Plasma cell
a differentiated B lymphocyte that is responsible for the generation and secretion of antibodies during the humeral response
Phagocyte
a group of leukocytes responsible for the endocytosis, of pathogens, foreign materials and cell debries
Physical barrier
a component of the first line of defence that features that features solid or fluid obstacles that block pathogen entry such as skin or mucus
Primary lymphoid tissue
components of the lymphatic system that are responsible for the production and maturation of the of lymphocytes. includes bone marrow and the thymus
Secondary lymphoid tissue
components of the lymphatic system that are responsible for the maintenance of mature lymphocytes and the activation of the adaptive immune response. includes lymph nodes and spleen.
T Lymphocyte
a type of lymphocyte that plays and important role in cell-mediated immunity. it differentiates into cytotoxic T cells, T helper cells and T memory cells
T memory lymphocyte (tm cell)
a differentiated T lymphocyte that is responsible for providing long-lasting immunological memory
adaptive immune system
antigen presenting cell APC
.
Helper T lymphocyte (Th cell)
a differentiated T lymphocyte that supports the functioning of a number of different immune cells, including the cloning and differentiation of selected T and B cells
immunoglobulin
an antibody
lymphocyte
a type of white blood cell that is apart of the immune system
MHC class I
expressed on all enucleated cells in th body. these mark cells as ‘self’ so that the immune system doesn’t attack them
MHC class II
expressed on antigen presenting cells, which interact with T helper cells in the process of antigen-presentation
cytotoxic T cell
a differentiated T lymphocyte that is responsible for the destruction of infected or abnormal cells
microbiological barrier
a component if the first line of defence in which the presence of normal flora limits the growth of pathogenic bacteria s
