Chapter 6 Foreign Invaders: Self versus non self

Disease

any condition that affects the normal functioning of either a part of an organism or the complete organsim

Non-infectious disease

a disease that cannot be transmitted from one organsims to another

Infectious disease

a disease that can be transmitted from one organism to another

Pathogen

a disease causing agent

Epidemic

the rapuid spread of an infectious disease to a large number of people within a population

Pandemic

an outbreak of an infectious disease that occurs over a wide geogrpahical area, affecting a large number of people

Host

an organism that has been infected by a pathogen

Vector

a living organism that carries and transmits a pathogen from one organism to another

Antigen

a unique marker on the surface of cells or viruses that is used in identification of self from non-self

Self antigen

an antigen on the surface of cells of an organism that is identified by the immue system as belonging to the organism (and therefore does not trigger an immune reponse)

Non-self antigen

an antigen on the surface of cells of an organism that is identified by the immune system as foreign the to organism (and triggers an immune response when detected)

MHC marker

a protein found on the surface of cells and is used in the identification of pathogens in the immune response

Epitope

the specific region of an antigen that is recognised by the immune system

MHC Class I marker

a type of protein marker on the surface of all nucleated cells that assists in the identification of self and non-self

MHC Class II marker

a type of protein marker on antigen-presenting white blood cells that is used in the activation of a specific immune response

Antigen presenting cell

a specific type of white blood cell that uses phagocytosis to engulf a pathogen before displaying peptide fragments (epitopes) on its MHC II markers for detection by white blood cells

Allergen

any substance that causes an allergic reaction

Cellular pathogen

living organism that causes disease within a host

Bacteria

unicellular, prokaryotic organisms with membrane bound organelles

Tetanus

a bacterial disease characterised by muscle stiffness and spasms

Spores (bacterial)

structures that bacteria form that aid in the survival of the organism under adverse environmental conditions

Fungi

a wide variety of eukaryotic organsims that include mushrooms, mould and yeasts

Terrestrial

describes any living organism that lives or grows on land

Hyphae

long, branching filaments that extend off the main body of the fungus and secrete digestive enzymes

Mycelium

a collection of hyphae

Tinnea

a common fungal infection that results in a red flakey rash in the area of the body that is affected

Rice blast disease

a fungal infection of rice that results in characteristic lesions and spots througout the plant's shoot system

Protozoa

unicellular, prokaryotic organisms that belong to the kingdom Protista

Heterotrophic

describes any organsims that obtains its nutrients by feeding on organic matter

Cilia

short microtubul projections from a cell that move to provide motility of the cell or fluid

Malaria

a serious disease caused by the Plasmodium protozoan which invades red blood cells when transmitted by mosquito vectors to the host

Endemic

the usual area where an organism is found

Non-cellular pathogen

a disease causing agent that lacks cellular structures and cannot replicate outside a host

Virus

a non-cellular pathogen that causes disease by taking over host cell machinery to rapidly produce identical virus copies, which then infect more host cells, disrupting normal functioning

Virion

a single virus particle existing outside a cell

Capsid

protective protein coat that surrounds the genetic material of a virion

Viral envelope

the lipid-based, outermost layer of the capsid of some types of viruses

Dormant

when a virus is present within a host but is inactive and therefore not currently causing symptoms associated with that disease

Haemagglutinin

a glycoprotein embedded in the viral envelope of the influenza virus, plays an important role in the attachment and entry of the virus to a host cell

Neuraminidase

a glycoprotein embedded in the viral envelope of the influenza virus, plays an important role in detachmentof new vrial particles from the host cell (allowing them to infect further host cells

Epidemology

a branch of medicine based on the study of disease distribution and control

Bacteriophage

a virus that specifically infects bacteria

Prion

a pthogenic protein with a mutant structure that can trigger normal proteins to fold abnormally, causing disease

PrPC

normal form of the protein associated with prions

PrPSc

disease causing mutant protein