Unit 4 // AOS1 Textbook Definitions Flashcards
The definitions of specific words that comes directly from the textbook.
Pathogen
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 an immune response. Also know as foreign antigen
Major histocompatibility complex (MHC) markers
A group of proteins present on the surface of all self-cells that enables the immune system to distinguish it from non-self material
Major histocompatibility complex class I (MHC Class I) markers
Expressed on all nucleated cells in the body. These mark cells as ‘self’ so that the immune system doesn’t attack them
Major histocompatibility complex class II (MHC Class II) markers
Expressed on antigen-presenting cells, which interact with T-helper cells in the process of antigen presentation
Autoimmune 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 and parasites
Non-cellular pathogen
A pathogen that neither has a cellular structure no exhibits the processes of a living organism. Examples include viruses and prions
Lysis
The disintegration or rupturing of a cell
Hyphae
Branching filaments of a fungus which helps absorb nutrients from the environment
Parasite
An organism that lives in or on another organism, usually deriving nutrition from the host organism
Innate Immune System
A component of the immune system that is composed of generalised and non-specific defences and/or responses to pathogens. Also known as the non-specific immune system
First line of defence
A component of the innate immune system characterised by the presence of physical, chemical, and microbiological barriers to keep pathogens out of the host organism
Second line of defence
A component of the innate immune system characterised by the non-specific response to injury and/or pathogens by a variety of cells and molecules
Non-specific
Describes a component of the immune system that responds the same way to all pathogens
Physical barrier
A component of the first line of defence that features solid or fluid obstacles that block pathogen entry such as skin or mucus
Chemical barrier
A component of the first line of defence that features the use of enzymes, toxins, and acids to protect against pathogen invasion
Cuticle
A waxy protective film covering the surface of a plant leaf
Gall
An abnormal outgrowth of tissue in plants designed to limit the spread of an invading pathogen
Trichomes
Small hairs on the surface of plants used to deter pathogens and/or insects
Microbiological barrier
A component of the first line of defence in which the presence of normal flora limits the growth of pathogenic bacteria.
Cilium (pl. cilia)
Thin, hair-like projection that protrudes from eukaryotic cells
Flora
Naturally occurring, non-pathogenic bacteria present in an organism
Leukocytes
A group of blood cells responsible for protecting the body against pathogens and foreign materials. Also known as white blood cells
Phagocytes
A group of leukocytes responsible for the endocytosis and destruction of pathogens, foreign material, and cell debris
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
Macrophage
A type of leukocyte found throughout the body that engages in phagocytosis and antigen presentation
Dendritic cell
A type of leukocyte that engages in phagocytosis and antigen presentation
Antigen-presenting cell
A subgroup of phagocytes that display antigens from consumed pathogens on their surface and interact with the adaptive immune response
Cytokine
A signalling molecule released by cells (typically in the immune system) which aids in communication between immune cells and helps protect against pathogens
Natural killer (NK) cell
A type of leukocyte responsible for the recognition and destruction of damaged and/or infected host cells
Mast cell
A type of leukocyte responsible for releasing histamine during allergic and inflammatory responses
Degranulation
The release of granule contents from a cell
Histamine
A molecule released by mast cells that plays a key role in inflammation
Inflammatory response
A series of biochemical events that occur in the body as a result of infection and/or trauma. Characterised by swelling, redness, pain, and heat in the affected tissue.
Eosinophil
A large granular leukocyte responsible for the release of toxic chemical mediators
