Chapter 12 - Communicable Disease Flashcards
1
Q
What is a pathogen
A
Disease causing microorganism
2
Q
Different types of pathogens
A
Bacteria
Fungi
Virus
Protoctista
3
Q
Vector definition
A
Living or non living factor that transmits a pathogen from one organism to another
Water, mosquito
4
Q
How do viruses infect
A
They take over cell metabolism
Viral DNA gets into the host
Their genetic material is inserted into host DNA
Uses host cell to make more viruses
Viruses reproduce rapidly and evolve to adapt to their host
Bust out of cell to infect others
5
Q
What are protoctistas
A
Eukaryotic organisms
Need a vector to transfer them to their hosts
6
Q
2 ways bacteria can be classified
A
By their shape
By their cell walls (gram staining)
7
Q
What are fungi
A
Eukaryotic organisms
Multicellular
Saprophytes - feed on dead + decaying matter , can be parasitic
8
Q
How do protoctistas infect
A
Take over cells and break them open
Digest the cells contents and use it to reproduce
9
Q
How do fungi infect
A
Digest living cells and destroy them
10
Q
How do bacteria infect
A
Produce toxins that damage the host cells by:
- breaking cell membranes
- damage enzymes
- interfere with hosts cells genetic material - can’t divide
11
Q
Diseases caused by bacterium
A
Bacterial meningitis
Tuberculosis
Ring rot
12
Q
Diseases caused by protoctistas
A
Potato / tomato late blight
Malaria
13
Q
Diseases cause by fungi
A
Athletes foot
Ringworm
Black sigatoka
14
Q
Tuberculosis affects
A
Animals - human and cattle
Damages and destroys lung tissue
Suppresses the immune system
15
Q
Diseases caused by viruses
A
Tobacco mosaic virus
HIV AIDS
influenza
16
Q
Bacterial meningitis affects
A
Humans (kids)
Cause blood poisoning
Rash
17
Q
Ring rot affect
A
Potatoes and tomatoes
Gram positive bacteria
Damages leaves, tuber and fruit
18
Q
HIV affects
A
Humans
Targets t-helper cells in immune system
Destroys immune system
Transcripts RNA to single strand of DNA
interacts with genetic material
19
Q
Influenza
A
Animals
Kills ciliated epithelial cells in gas exchange system
Airways open to infection
20
Q
Tobacco mosaic virus
A
Plants
Damages leaves, flowers, fruit
Stunts growth
21
Q
Black sigatoka
A
Banana plants
Attack’s and destroys leaves
Turn black
22
Q
Ring worm
A
Cattle
Grey white crusty areas in skin
Itchy
23
Q
Athletes foot
A
Humans
Grows on and digests warm moist skin
Causes cracking and scaling, itchy
24
Q
Potato blight
A
Potatoes and tomatoes
Destroys leaves, tuber, fruits
25
Malaria
Humans animals
Female mosquitos
Plasmodium passed on to people
26
What is direct transmission
Pathogen is transferred directly from one individual to another
27
Example of direct transmission
- Direct contact
- Inoculation - through cuts, break in skin
- Ingestion
28
What is indirect transmission
Pathogen travels from one individual to another via an intermediate
29
Examples of indirect transmission
Air , water, food, another object
Fomites- inanimate objects (socks)
Vectors- mosquitos
Spores- in air and water
Soil contamination
30
How do living conditions affect disease transmission
Overcrowded conditions increase disease transmissions
TB - droplet infection (directly)
- remain in air (indirectly)
31
How does climate affect disease transmission
Increased rainfall and wind - promote spread
Damp warm conditions increase disease survival
Potato late blight - spores spread
Mosquitoes - warm - ideal for breeding
32
How social factors affect disease transmission
High when
Limited access to:
Healthcare
Education
33
Preventing communicable disease in plants
```
Plant crops with space in between
Clear fields throughly when harvesting
Rotate crops
Control insect vectors
Hygiene practices - sterilising
```
34
How do plants recognise an attack
Receptors in cell membranes respond to molecules from pathogens
Stimulates release of signalling molecules
These trigger cellular responses by switching on genes
Responses = producing defensive chemicals
35
What physical defences do plants have
-Waxy cuticle =
barrier, stop water collecting on leaf - reduce infection transferred
-Cell walls
-produce Polysaccharide called CALLOSE =
Deposited between cell wall and plasma membrane
- harder for pathogens to enter
- at plasmodesmata = limit spread of virus between cells
- blocks sieve plates in phloem
36
What chemical defences to plants have
Produce antimicrobial chemicals (antibiotics)
- kill invading pathogens, inhibit their growth - interfere with cell membranes
- saponins / phytoalexins
Secrete chemicals toxic to insects
- reduces plant viruses carried by insect vectors
- cyanide
37
How does skin prevent infection
blocks pathogens from entering body
| produces antimicrobial chemicals - lower pH , inhibiting growth of pathogen
38
How does woUnd repair prevent infection
Skin can repair itself by reforming a barrier against pathogen entry
- surface is repaired by outer layer of skin cells dividing and migrating to the edges of wound
- tissue below contracts to bring edges closer together
- repaired using collagen fibres
39
How does expulsive reflexes prevent infection
Sneezing and coughing - expel foreign objects from the body (mucous membrane)
Vomiting and diarrhoea - expel contents of gut along with pathogens
40
How do fevers get rid of pathogens
Raise body temperature
Inhibits pathogen reproduction
Immune system works faster
41
How does Mucous membranes prevent infection
protect the body openings that are exposed to the environment
secretes mucus that traps pathogens
contains phagocytes
contains lysozymes that destroy bacterial + fungal cell walls
42
How does blood clotting prevent infection
blood clot is a mesh of protein fibres
take place when platelets are exposed to damaged blood vessels
plug wounds
prevent pathogen entry
stop blood loss
43
How does inflammation prevent infection
damaged tissue activates mast cells that release histamines and cytokines
```
histamines
increases the permeability of the blood vessels
- leak fluid into surroundings
- cause swelling
* isolate the pathogens that have entered the damaged tissue
cause vasodiliation
- increases the blood flow
- makes the area hot
```
cytokines
- brings white blood cells to fight of pathogens
44
How is phagocytosis carried out
Neutrophils and macrophages
Phagocytes are attracted to chemicals produced by pathogen
Phagocytes recognise the pathogen as non self
Phagocytes engulf pathogen by surrounding it with cell surface membrane until it pinches off to form vesicles called / cytoplasm moves around pathogen = phagosome
Phagosome fuses with lysosome to form = phagolysosome
Enzymes from lysosome digest and destroy pathogens
45
What are the 2 types of white blood cells
Neutrophils - multi lobed nucleus
Macrophage
46
What is an antigen
Molecules found on the surface of cells that trigger immune response
47
How are antigen presenting cells formed
Macrophages
Macrophage digests everything but antigens
Combines the antigens from the pathogen surface membrane with glycoproteins in the cytoplasm called = Major Histocompatibility Complex = MHC
The MHC complex moves these antigens to the macrophages surface membrane to become = APC
48
What is an APC
A cell that presents foreign antigens complexed with MHCs on its own cell surface membrane
49
What does MHC stand for
Major Histocompatibilty complexes
50
What do the cytokines released by phagocytes do
Proteins that act as messenger molecules
Informing other phagocytes that the body is under attack
Stimulating other phagocytes to move to infected area
51
Why are opsonins useful chemicals in phagocytosis
Chemicals that bind to pathogens and tag them
So they’re more easily recognised by phagocytes
Allow phagocytes to get closer to pathogens
52
Examining blood smears
What will you see
Red blood cells
Platelets = fragments of cells involved in blood clotting
Neutrophils
Monocytes
Lymphocyte
53
Visible features of
| Neutrophils
- Multi lobed nucleus
| - Grainy cytoplasm
54
Visible features of
Lymphocytes
- smaller than neutrophil
| - nucleus takes up most space
55
Visible features of
Monocytes
- Biggest white blood cell
- Kidney bean shaped nucleus
- No grainy cytoplasm
56
What is the structure of an antibody
Y shaped glycoprotein called immunoglobulin
Made of 2 identical long polypeptide chains = heavy chain
2 dental short polypeptide chains = light chain
Chains are held together by disulfide
Hinge region = allows flexibility when the antigen binds to the antibody
Binding site = variable site - gives specificity
Allows binding to receptors on immune system = constant region
57
How do antibodies prevent the pathogen binding to human cells
- pathogens can’t invade host cells when part of an antigen-antibody complex by blocking the cell surface receptors the pathogen needs to bind to the host
58
Outline action or opsonins
- antigen-antibody complex acts as an opsonise so complex is more easily recognised an engulfed by phagocytes
59
Outline actions of agglutinins
- anti bodies act as agglutinins - causing pathogens carrying antigen-antibody complexes to clump together - prevents from spreading - easier for phagocytes to engulf at same time
60
Outline actions of antitoxins
Antibodies called antitoxins
Bind to toxins produced by pathogens
Prevent toxins from affecting human cells
Toxins are neutralised
61
What is the function of antibodies
- acts as an opsonin
- are agglutinins
- can neutralise toxins
- prevent from binding to human cells
62
What is active immunity
Immunity you get when your own immune system makes its own antibodies after being stimulated by antigens
63
What are the 2 different types of active immunity
Natural
Artificial
64
What is a example of
Natural active immunity
You become immune after catching a disease
You produce your own antibodies
65
What is a example of
Artificial active immunity
When you become immune after being given a vaccination
A weakened or dead pathogen
66
What is passive immunity
Immunity you get from being given antibodies by a different organism
67
Example of
Natural passive immunity
A baby gaining antibodies from mothers breast milk, or placenta
Colostrum
68
Example of
Artificial passive immunity
Immune after being injected with someone else’s antibodies
If you have tetanus, you are injected with antibodies against the tetanus toxin, from blood donations
69
What are the differences between active and passive immunity
Active
- long term
- creates memory cells
- takes time for protection to develop
- requires exposure to antigen
Passive
- short term
- takes immediate effect
- doesn’t create memory cells
- does not need antigens
70
What is cell mediated immunity
T lymphocytes respond to cells of an organism that have been altered
71
How does cell mediation work
Non specific defence of phagocytosis = produces APC
The CD4 receptors on the T helper lymphocytes meets a complementary antigen on an APC and binds to it - This activated the T-helper cells in a process called CLONAL SELECTION
Then undergoes CLONAL EXPANSION the T helper cells release interleukins and divide by mitosis and differentiate into different types of T cells that carry out different functions
72
What 4 things can cloned T cells do
Develop into T memory cells
Develop into T killer cells
They can release interleukins to increase phagocytosis
They can release interleukins to stimulate the division of B lymphocytes Increases antibody production
73
Name the 4 different types of T lymphocytes
T killer
T memory
T helper
T regulatory
74
What donT helper cells do
Their CD4 receptors bind to antigens on APC
Release interleukins
Which stimulate B cells
Produce different T cells
Stimulates macrophages to INGEST pathogens with antigen - antibody complex
75
What do T killer cells do
Destroy the pathogen carrying antigens
By producing a chemical called = perforin
That kills the pathogen
By making holes in cell surface membrane
Freely permeable
76
What do T memory cells do
Part of immunological memory
Remembrer the specific antigens
So when met again
Will divide rapidly to produce specific T killer cells
To destroy pathogen
77
What do T regulator cells do
Suppress the immune system
From other white blood cells
Once pathogen has been eliminated
To prevent autoimmune response
Interleukins important
78
What is humoral immunity
Produces antibodies to respond to foreign antigens
79
How does humoral immunity occur
B lymphocytes are covered with antibodies
These antibodies join with the complementary antigens on the pathogen
The B cell engulfs and processes the antigen to become a B cell APC
T helper cells bind to the B APC = CLONAL SÉLECTION
(B cell with correct antigen is selected for cloning)
T cells produce interleukins that activate B Cells to divide by mitosis = CLONAL EXPANSION
80
Why do B cells differentiate into
Plasma cells
B Effector cells
B Memory cells
81
What do plasma cells do
Primary immune response
Produce antibodies to a particular antigen
Release them into circulation
Disable antigens
Act act opsonins, agglutinins, antitoxins
82
What do effector cells do
Divide to form plasma cell clones
83
What do B memory cells do
Secondary immune response
Provide immunological memory
Programmed to remember antigen
Enables body to respond quickly when pathogen reenters
84
Why is the primary response slow
Antigens on pathogen active immune system
Not enough B lymphocytes to produce right antibody
Eventually will produce enough antibody - show symptoms
After exposure to antigen T + B make memory cells
85
Why is the secondary response faster
Immune system produces stronger, faster response
B Memory divide into plasma cells = make antibodies
T Memory divide into T cells to destroy pathogen
Before symptoms show
86
What is an auto immune disease
Response when the immune system acts against its won cells and destroys healthy tissue
Recognises “self cells” as foreign
87
Rheumatoid arthritis
Joints
Feet, wrists
Cure = anti inflammatory , immunosuppressant, steroids
88
Lupus
Affects skin and joints
Can attack organs
Cure = immunosuppressant, anti inflammatory, steroids
89
What are the principles of vaccination
1) pathogen is made safe so no risk of infection
- dead, inactivated, altered, attenuated
2) small amounts of safe antigen injected into blood
3) primary immune response triggered
4) memory cells made
5) come into contact again - secondary response is quicker and stronger
90
What is herd immunity
When most people in a community are vaccinated the disease become rare
Even people without the vaccines are unlikely to get it
Reduces the risk of an epidemic
91
What are routine vaccines
MMR =
- measles , mumps , rubella
- children
Meningitis C vaccine =
- protects against bacteria that causes Meningitis C
- 3 months, 1 year, teenager
92
Reasons for changes in vaccines and vaccination programmes
Influenza
Antigens on influenza surface change regularly
Forming new strains of virus
Memory cells from virus against 1 strain will not impact new strains
New vaccines are made every year that are most effective against the recent circulating viruses
93
Why do possible sources of medicine need to be protected
Uses natural compounds
Plants, animals, microorganisms
Penicillin = fungus
Cancer drugs = soil bacteria
Alzheimer’s = daffodils
94
What are personalised medicines
Tailored to an individuals genes
Doctor can predict how you will respond to medicine, and prescribe you the most effective using your genetic material
95
What is synthetic biology
Uses technology to design artificial proteins, cells, microorganisms
Cancer
- destroy cancer cells while leaving body healthy
96
Benefits of using antibiotics
Kill or inhibit growth of bacteria
| Doesn’t damage human cells = isolated
97
Disadvantages of antibiotics
Can cause severe allergic reactions
Can form antibiotic resistance
- mutations occur so they become naturally resistant, spread the advantageous gene
Prevent by not giving to small infections
Making sure the course of medicine is ended so all bacteria is killed off
98
MRSA
Causes serious wound infection
| Resistant to meticillin
99
Clostridium difficile
Harmless bacteria in digestive system killed, expect Cdifficile
Produces cramps, fevers, diarrhoea
