UNIT 4 6A: Recognising self from non-self Flashcards
Disease
Any condition that affects the normal function of either a part of an organism or the complete organism
Non-infectious Disease
A disease that cannot be transmitted from one organism to another
Infectious Disease
A disease that can be transmitted from one organism to another
Pathogen
A disease-causing agent
Epidemic
The rapid spread of an infectious disease to a large number of people within a population
Pandemic
An outbreak of infectious disease that occurs over a wide geographical area, affecting a large number of people
Host
An organism that has been infected by a pathogen
Vector (Immunity)
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 the identification of self from non-self
Self Antigen
An antigen on the surface of cells of an organism that is identified by the immune system as belonging to the organism and therefore does not trigger an immune response
Non-self antigen
An antigen on the surface of cells of an organism that is identified by the immune system as foreign to the organism and triggers an immune response when detected
MHC Marker (Major histocompatibility marker)
a protein that is 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 1 marker
A type of protein marker on the surface of all nucleated cells that assists in the identification of self from non-self
MHC Class 2 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 (APC)
A specific type of white blood cell that uses phagocytosis to engulf a pathogen before displaying peptide fragments (epitopes) on its MHC Class 2 markers for detection by white blood cells
Allergen
Any substance that causes an allergic reaction
What are the top 2 causes of death worldwide
heart disease
Stroke
Examples of contact transmission
Handshaking
Bodily fluid exchange
Infected blood or body fluids from drinking glasses, toothbrushes
Examples of medium transmission
Airborne
Waterborne
Foodborne
Carrier
Is a living organism that is infected by the pathogen it is carrying, and carries and transmits a pathogen from one organism to another
What are 2 common vector-borne diseases
Dengue
Malaria
What is the course of disease
1.Incubation
The pathogen may take time to multiply to a number sufficient to cause disease
May take time to reach target tissue which is susceptible to its actions
- Symptoms of disease
Symptoms are the result of the body attempting to eliminate the infection
OR are the effect the pathogen has on the body of the host
3.Recovery
The final stage of the disease
If the pathogen cannot be eliminated, then disability or death is likely
Role of MHC markers
Their role is to identify a cell as ‘self’ if healthy, and ‘non self’ if infected by a pathogen, by presenting small peptides to circulating immune cells
Why are allergens not considered pathogens
Allergens are not considered to be pathogens because pathogens elicit an immune response in all individuals (with or without symptoms) whereas an allergen only affects individuals who have a specific sensitivity to it
What is the cause of the symptoms associated with an allergic response
The symptoms associated with an allergic response are due to a process known as hypersensitivity.
