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assessment 3 Flashcards

1
Q

define infectious disease

A

disease which can be transmitted from one organism to another, and are caused by pathogens

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2
Q

define pathogen

A

any organism capable pf causing disease

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3
Q

list the 5 types pathogens

A 
bacteria
fungi
protozoans
viruses 
prions
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4
Q

define bacteria

A

prokaryotic, unicellular organisms, which don’t have membrane bound organelles and are each made of one cell.
pathogenic bacteria can cause disease, usually by releasing toxins or damaging host issues.

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5
Q

example of a bacteria that causes disease

A

tuberculosis - caused by the bacterium mycobacterium tuberculosis, the bacteria enters the lungs when a person inhales infectious droplets

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6
Q

define fungi

A

eukaryotic, non-photosynthetic, hetertrophic organisms with a cell wall. Can be unicellular or multicellular
The damage caused by fungi mostly arises from the enzymes they produce.

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7
Q

example of fungi that causes disease

A

TINEA
Mode of transmission = direct contact, skin to skin contact, surfaces e.g. shower floor
The fungi lives in the outside the layer of the human skin, where they produce chemicals which break down keratin

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8
Q

define protozoans

A

unicellular microorganisms wiht internal membranes. Eukaryotic with a complex lifestyle.

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9
Q

example of a protozoan that causes disease

A

MALARIA
caused by plasmodium
- plasmodium floasts freely int he blood of an infected person, it feeds on haemoglobin in the RBC’s causing them to pop

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10
Q

define viruses

A

non-cellular entities (non-living), consisting og a single type of nucleic acid (RNA or DNA) encased in a protein coat.

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11
Q

how does viruses reproduce

A

The virus attaches to a host cell, which it then penetrates. It hijacks the hots enzymes and nutrients to make its own viral proteins and nucleic acid
- The viral materials assemble into new viruses which are released from the host cell and infects other cells

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12
Q

example of a virus that causes disease

A

COVID 19

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13
Q

define prions

A

protein that has been altered from its normal structure and can then alter other proteins to develop more prions, so that change spreads like a chain reaction

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14
Q

what tissues does prions normally affect

A

brain and neural tissue - leads to neurodegeneration

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15
Q

example of a prion that causes disease

A 
SPONGIFORM ENCEPHALOPATHY (MAD COW DISEASE) IN CATTLE
Progressive, degenerative and fatal disease affecting the central nervous system in cattle  
HUMAN FORM = CREUTZFELDT-JAKOB DISEASE
symptoms incl. loss of intellect, changes in personality, loss of co-ordination
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16
Q

what are the 3 modes of transmission

A
  1. direct contact
  2. indirect contact
  3. vector
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17
Q

what is direct contact (mode of transmission)

A

physical contact between an infected organism and a susceptible organism allows the transfer of infected bodily fluids

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18
Q

types of direct contact include …

A

person to person

droplet spread

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19
Q

e.g. of diseases that come from person to person contact (direct)

A

STD’s, ring worm, needle injections

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20
Q

e.g. of diseases that come from droplet spread (direct contact)

A

tuberculosis, measles, small pox

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21
Q

what are types of indirect contact

A

airborne
contained object (fomites)
contaminated food and drinking water (vehicular)

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22
Q

explain fomites as a type of indirect contact + e.g.

A

when organisms can live on objects or a short period of time e.g. door knob, railing…
E.G. E. Coli

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23
Q

explain vehicular transmission + e.g.

A

transmission through contaminated food and water

E.G. E. Coli

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24
Q

what are vector borne

A

the transfer of the pathogen via another object such as an insect

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25
vector transmission example
malaria caused by plasmodium plasmodium is a pathogen that floats in the blood of an infected persona and needs on haemoglobin causing RBC to pop
26
how did koch build on germ theory
koch isolated and gre the bacteria responsible for causing anthrax
27
what is kochs postulates?
list of criteria which must be met to prove that a particular organism causes a particular disease
28
list kochs postulates
1. in every case 2. must be able to be grown in pure culture 3. same symptoms as the original host - (disease must be able to be reproduced) 4. the disease must be able to be produced
29
what theory did pasteur have the idea of
microbial fermentation theory
30
what is pasteurisation
a technique to kill the germs he had discovered, by boiling the wine before cooling it
31
what is the goal of the barriers of infection
to prevent pathogens from entering your body
32
what are the three types of barriers of infection
physical, chemical, microbiological
33
define physical barriers (of infection)
barriers which physically block a pathogen from entering your body
34
examples of the physical barriers to infection
skin, mucus membranes, cilia, urine, saliva, eyelids
35
how does mucus membranes act as a physical barrier to infection
Mucus membranes line the openings of your body which arent covered in skin E.G. Respiratory, digestive, reproductive and urinary - prevents membranes from drying out - traps unwanted pathogens and substances until they can be removed from cilia - contains lysozyme to help break down microbes
36
how does cilia act as a physical barrier to infection
cilia is small hair-like projections that extend from the epithelial cells and line the respiratory tract
37
how does saliva act as a physical barrier to infection
swallowing saliva washes microbes from the teeth and mouth
38
how does eyelids act as a physical barrier to infection
wipes pathogens away
39
define chemical barriers (barriers of infection)
chemical barriers make the body surfaces inhospitable to pathogens
40
how does lysozyme act as a chemical barrier to infection
lysozyme is an enzyme that breaks down the cell walls of bacteria, killing them and helping to fight infection found in tears, saliva, mucus
41
how does acidic secretions act as a chemical barrier to infection
they contain degradative enzymes like lysozy,e body secretions also chemically screen out pathogens by being very acidic (low pH) acid secretions are produced in vagina, ear canal, stomach, skin
42
define microflora
microorganisms in our body which dont cause harm
43
what does microflora aid our body
1. compete for space and nutrients. The body has space for pathogens to live and grow in food and to feed off. A pathogen doesn't have a chance to establish itself in the body because it is already being used by microflora 2. produce antimicrobial chemicals antimicrobial chemicals which prevent the growth of other organisms. The acidity of the skin results from the activity of microflora, which break own the sebum your skin to form fatty acids.
44
what is the goal in the innate immune system
to stop foreign materials spreading around the body and causing more damage.
45
characteristics of innate system
- non-specific - responds rapidly - doesn't adapt hence innate
46
what are the components of the innate immune system
phagocytosis natural killer cells inflammation the complement system
47
define phagocytosis
the process by which phagocytes engulf and destroy foreign or unwanted material e.g. pathogens
48
what are phagocytes
WBC or leukocytes. WBCs are designed to protect the body against invaders
49
what are the phagocytes e.g.s
neutrophils macrophages mast cells
50
what are the steps in phagocytosis
1. the phagocyte engulfs the foreign material, forming a phagosome 2. a lysosome fuses with the phagosome, forming a phagolysosome 3. within the phagolysosome the enzymes break down the foreign material into smaller pieces 4. the small waste fragments are expelled from the phagocyte by exocytosis. this residual vesicle fuses with the plasma membrane and the contents are released.
51
what are neutrophils involved in
PHAGOCYTOSIS - quickly enter tissues and phagocytose pathogens in acute infection ANTIMICROBIAL COMPOUNDS - release hydrogen peroxide which disrupts bacterial and fungal cell membranes killing RELEASE CYTOKINES which attract other immune cells and promote inflammation
52
what are macrophages involved in
PHAGOCYTOSIS they live longer than other phagocytes so they help fight chronic infections ANTIGEN PRESENTATION Present some antigenic fragments on their surface. It then meets up with T lymphocytes and activated them RELEASE CYTOKINES
53
what are dendritic cells involved in
phagocytosis | antigen presentation
54
what are natural killer cells
they constantly patrol the body, and are important in the defence virus-infected and cancerous cells
55
what do natural killer cells do
- they release cytotoxic chemicals (chemicals which can kill cells directly) - they only release cytotoxic chemicals when they're in close proximity to the target cells
56
e.g. of natural killer cells
perforin - punches holes in the cell membrane of the target cell, killing it
57
what is inflammation
the accumulation of fluid, plasma proteins and white blood cells that occurs when tissue is damaged or infected
58
symptoms of inflammation
redness, heat, swelling, pain, loss of function in the affected area
59
steps in the inflammatory response
the pathogen successfully makes it through the first line of defence or the body tissues get damaged. injured cells release chemokines (chemokine have many functions incl. attracting neutrophils
60
what are the goals of inflammation
confine the pathogen to one area destroy the pathogen remove the pathogen, its products and any damaged tissue
61
what is the complement system
a set of more than 30 different proteins which float around in the blood
62
when is the complement system activated
when the pathogen breaks through the barriers to infection
63
what are results of the complement system
- punching holes in the cell membrane or wall of the pathogen - promoting inflammation - opsonisation, where these proteins flag the antigen for removal
64
what are the two types of immunity involved in the adaptive immune system
antibody-mediated cell-mediated
65
what are B lymphocytes
a type of WBC which is produced int he bone marrow
66
explain the lifecycle of B lymphocytes
1. they are produced and mature in the bone marrow 2. once matured they are released in to the blood 3. they accumulate in the lymphoid tissues 4. when a b lymphocyte comes into contact with a specific antigen it becomes activated 5. once triggered by an antigen, it begins to proliferate to form millions of clones
67
list the two types of B lymphocytes
plasma cells | memory B lymphocytes
68
what is the function of plasma cells
- produces antibodies that either: make the pathogen unable to cause damage or makes it easier for other components of the immune system to destroy it. - proteins which bind to specific antigens
69
list 4 antibody strategies
neutralisation precipitation agglutination activating complement system
70
what is the antibody strategy of neutralisation
deactivating a pathogen or toxin by blocking its active site
71
what is the antibody strategy of precipitation
antibodies bind to soluble anitgens causing them to form insoluble clumps
72
what is the antibody strategy of agglutination
antibodies bind to antigens on the surface of cells to form clumps of cells
73
what is the antibody strategy of activating complement system
to help disarm pathogens, enhancing phagocytosis, inflammation and pathogen removal by cell lysis
74
what is the function of memory B lymphocytes
- provides immunological memory | - acts as a long term defence against antigens
75
how does memory b lymphocytes work
- If the animal is exposed to the same antigen again, memory cells recognise it can divide to produce antibody-producing plasma cells
76
benefits of memory b lymphocytes
faster stronger longer lasting as the body has already met the antigen before
77
what cell is involved in cell-mediated immunity
t lymphocytes
78
what cell is involved in antibody mediated immunity
b lymphocytes
79
what are t lymphocytes
a type of WBC which is produced in the bone marrow
80
explain the life cycle of T lymphocytes
1. produced in bone marrow 2. they are released into the blood and mature in the thymus gland 3. once they mature, theyre released into the blood again where they circulate in an inactive state 4. if a T lymphocyte comes into contact with its specific antigen, the receptors on its surface allows it to bind it and the cell becomes activated.
81
list the types of T lymphocytes
cytotoxic (killer T cells) helper supressor memory
82
what is the function of T lymphocytes
kill foreign, infected and abnormal cells they also sometimes kill the body's own cells cytotoxic T lymphocytes secrete or inject toxic chemicals into the target cells
83
function of helper T lymphocytes
- Help promote the activities of other immune responses - Secrete cytokines which: 1. Increase the activity of phagocytes 2. Help promote inflammation 3. Stimulate the production of cytotoxic T lymphocytes 4. Stimulate B lymphocytes to differentiate to form plasma cells and memory B lymphocytes
84
function of supressor T lymphocytes
- Turn off the immune response after the antigen has been successfully contained, destroyed or removed
85
function of memory T lymphocytes
- Provide the body with long term defence against antigens
86
what is an antigen
any molecule that the body recognises as foreign and that triggers an immune response
87
what is immunity
the ability to recognise foreign substances, and destroy them

YR 12 BIO (10 decks)

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