Diseases --> Semester 2 Flashcards
Disease definition –> and the 3 types
A condition or change that negatively impacts the normal functioning of an organism.
the three types are:
- non-infectious
- congenital
- infectious
Infectious disease definition
can be spread
transmitted from organism to organism. all are caused by pathogens
Non-infectious disease definition
cannot be spread
disease that cannot be passed from one individual to another, they are caused by physical factors
Pathogen and 5 Types
A pathogen is an organism causing disease to its host,
viruses, bacteria, parasites, fungi, protists
what is Airborne transmission
airborne droplets remain suspended in the air.
commonly transmitted through small respiratory droplets. These droplets are displaced when someone with the airborne disease sneezes, coughs, laughs, or otherwise exhales in some way.
what is Vector-borne transmission
vectors such as arthropods are living carriers of pathogens. Occurs when a pathogen lives on the surface of the vector, pathogen transmitted directly from vector to host
what is Contact Transmission
direct or indirect
pathogen being transmitted from person to person (touching, kissing, or sexual contact)
what is Vehicle transmission
non-living pathogen carriers. called fomites (clothes, utensils, furniture, door-knobs)
1st line
Physical
- skin (keratin)
Chemical
- lysozyme
- mucus
- stomach acid
Mechanical
- coughing
- sneezing
2nd line
Complement system
- 25 proteins
Interferons
- proteins that disrupt viral replication
Inflammation
- involves phagocytosis
how can an increase in core body temp help body fight against infection
slows down pathogen growth and increases the rate of phagocytosis by WBC (white blood cells)
phagocytes have an organelle called what? and what does it contain?
lysosomes that contain digestive enzymes for destroying pathogens
what system and fluid can WBC be found?
lymphatic system and lymph fluid
3 lines of defence
- physical, chemical & mechanical barriers
- non-specific (innate)- immune system
- specific (adaptive)- immune system
Distinguish between the two types of immunity:
Innate (non-specific)
Acquired (specific)
how can the immune system distinguish between non-self cells and self cells?
by recognising antigens.
–> signalling structures unique to a specific cell.
why are antibodies only effective against a specific pathogen?
the shape is complementary to the shape of antigen on pathogen
t-cells are involved in what?
specific immune response to infection
3 types of t-cells in specific immune response
cytotoxic t-cells
helper t-cells
memory t-cells
cytotoxic t-cells?
release perforin and cause apoptosis
helper t-cells?
help activate b-cells and cytotoxic t-cells
memory t-cells?
contain antigens specific for certain pathogen
4 points of entry
respiratory surfaces
wounds
digestive system
reproductive organs
acquired? (adaptive?)
specific defences
- cell-mediated
- humoral
innate?
non-specific defences
- physical, chemical and mechanical
- phagocytosis and inflammation
phagocytosis is what?
The process when cell is trying to destroy something,
- virus or infected cell,
- often used by immune system cells.
phagocytosis steps
- engulfs pathogen
- phagosome forms
- phagosome fuse with lysosome –> phagolysosome
- digestive acids and enzymes destroy pathogen
- digested pieces released into extracellular space by exocytosis
define immunity
ability of host to resist infectious disease
categories of protection in non-specific immune response
physical and chemical barriers, the inflammatory response, and interferons.
specific immune response is triggered by what
triggered by antigens
example of physical protection
skin –> makes hard protective layer
example of chemical protection
tears –> cells in eye produce and secrete range of chemicals including enzymes
example of mechanical protection
blinking –> reflex action to irritation by particles (pathogens)
what are non-self pathogens (molecules) called
antigens
symptoms of inflammation
swelling
heat
redness
pain
what is an antigen
causes the body to make an immune response
infection steps
- host access gained
- attachment to host cells
- survive host defences
- replicate and cause host cell apoptosis
inflammation steps
- bacteria invade, chemical messengers released (histamine).
- platelets cause blood clot, WBC arrive
- phagocytes (macrophages and neutrophils) digest bacteria, tissue heals
what does a phagocyte do? and another name?
macrophage & neutrophils
recognise, engulf and kill pathogens by process –> phagocytosis
what do lysosomes do in phagocytosis
fuses with phagosome –> phagolysosome
they consist of acids, oxidisers and enzyme
these chemicals decompose/breakdown pathogens
what do memory t-cells do
recognise/remember pathogen if returned
how are cytotoxic t-cells activated?
interleukin-2 released by helper t-cells –> leads to development of cytotoxic t-cells
what is role of cytotoxic t-cells in immune response?
detect antigen and release protein called perforin
results in cell burst
2 types of b cells
plasma cells and memory b cells
congenital
genetically inherited
all disease is caused by what?
pathogens
epidemic
national spread of a disease
pandemic
international spread of disease
what cause the body to make immune responses
antigen
role of interleukin1
activate B and T cells
what is apoptosis
cell death
3rd line
- phagocyte engulfs pathogen and becomes APC
- Helper T-cell binds to antigens on APC
- phagocyte (APC) releases interleukin-1
- Helper T-cells release interleukin-2
APC = antigen presenting cell (pathogen)
3rd line cell mediated
- phagocyte engulfs pathogen and becomes APC
- Helper T-cell binds to antigens on APC
- phagocyte (APC) releases interleukin-1
- Helper T-cells release interleukin-2
- growth and development of cytotoxic t-cells (killer t-cells)
- killer t-cells bind to infected host cells and release perforin
- perforin causes holes in membrane of infected cells
- cell bursts and dies (apoptosis)
3rd line humoral
- phagocyte engulfs pathogen –> APC
- Helper T-cell binds to antigens
- phagocyte (APC) releases interleukin-1
- Helper T-cells release interleukin-2
- growth of b cells –> plasma & memory
- plasma cells produce antibodies
- antibodies bind to pathogens
neutralisation?
3rd line humoral –> (step 7, antibodies bind to pathogen)
antibodies bind to pathogen antigens and prevent penetration into host cells
agglutination?
3rd line humoral –> (step 7)
antibodies bind to pathogens ‘glue’, them together and reduce mobility
what is cell mediated?
an immune response that does not involve antibodies
complement system?
promotes inflammation, and attacks the pathogen’s plasma membrane.
