1
Q
what is the first line of defence?
A
physical and chemical barriers that stop pathogens from entering in the first place.
2
Q
what is the second line of defence?
A
when a pathogen gets past the first line of defence
3
Q
what is the third line of defence?
A
a specific immune response that targets specific pathogens using lymphocytes
4
Q
what are 3 examples of first line defence?
A
- skin
- mucous membranes
- secretions of skin and mucous membranes
5
Q
what are 3 examples of second line defence?
A
- fever
- anti microbial proteins
- inflammatory response
6
Q
what are 3 examples of third line defence?
A
- lymphocytes
- antibiotics
- memory cells
7
Q
what do the Lachrymal glands do?
A
Lachrymal glands near eye produce tears containing lysozymes to wash away dust/dirt.
8
Q
what does the linings of the body do?
A
Linings of the body openings in
nose/throat produce mucus to help trap foreign particles
9
Q
what do the Lymph nodes do?
A
Lymph nodes trap foreign particles and contain white blood cells.
10
Q
what does the stomach do?
A
Stomach produces acid that kills microbes before they reach intestine
11
Q
what does your skin do?
A
Skin is a surface barrier to most diseases.
12
Q
what does saliva do?
A
Saliva contains substances to resist and remove microbes. First Line of Defence
13
Q
what does the outer layer of skin do?
A
The outer layer of skin (epidermis) is tough and waterproof, preventing pathogens from entering.
14
Q
what is the outer layer of skin made of?
A
It’s made of tightly packed dead cells that are hard for microbes to penetrate
15
Q
what does the outer layer of skin contain?
A
It contains its own population of harmless bacteria that help prevent other microbes from multiplying
16
Q
what does the thick layer of mucus do?
A
thick layer of mucus which traps entering pathogens
17
Q
how are the pathogens released from the mucus?
A
coughing or sneezing
18
Q
what do the antibodies in the mucus do?
A
Mucus can also contain antibodies that prevent bacteria and viruses from attaching to the surface.
19
Q
what does mucus provide?
A
Mucus provides a moist, nutritious layer for the harmless (beneficial/commensal) microbes to live and produce substances that inhibit the
growth and entry of pathogens.
20
Q
what is cilia?
A
Cilia are tiny ‘hairs’ that line the
respiratory surfaces of the trachea and bronchial tubes.
21
Q
how do cilia work?
A
Cilia are constantly beating in an upwards direction to move the mucus containing trapped pathogens upwards to the throat, where it is removed by
coughing, sneezing, or swallowing.
22
Q
what are the 2 second line defences?
A
- Inflammatory Response
- Phagocytosis
23
Q
what is there on the surface of body cells?
A
On the surface of body cells, there are ‘marker’ molecules that identify the cell as ‘self’.
24
Q
what happens when pathogens enter the cell?
A
When pathogens enter the body, they have chemical markers called antigens that our immune system detects as being ‘non-self’ – kind of like an ID badge!
25
what are antigens?
Antigens are molecules (often proteins) that the immune system recognises
26
what does plasma contain?
- salts/minerals
- water
- proteins
27
what does the buffy coat contain?
- white blood cells
- platelets
28
what are white blood cells (wbc) also known as?
leukocytes
29
what are the types of white blood cells?
30
what is a phagocyte?
Phagocytes are specialised white blood cells that engulf and digest foreign particles (pathogens) and cellular debris
31
what are the 3 main types of phagocytes?
1. Neutrophils
2. Macrophages
3. Dendritic Cells
32
what are neutrophils?
first to get to the site of infection
33
what are macrophages?
o Can stay in tissues or travel from blood vessels into the infected tissue
o They destroy the pathogen and present parts of the antigen on its surface
34
what are dendritic cells?
They are highly specialised to present antigens to Helper-T cells
35
what are self antigens?
Self-antigens are found on the body’s own cells; normally ignored by the immune system.
36
what is autoimmune disease?
In autoimmune diseases, the immune system mistakenly recognises self-antigens as non-self, attacking the body’s own cells (e.g., Type 1 diabetes, multiple sclerosis).
37
REMEMBER TO DO PHAGOCYTE SLIDE, LEARN BY DIAGRAM ON PAPER
38
REMEMBER TO DO INFLAMMATORY RESPONSE SLIDE, LEARN BY DIAGRAM ON PAPER
39
what cells can be displayed on the surface?
Dendritic Cells, Macrophages, and B- cells can display part of the pathogen on their surface
40
what is your Lymphatic System?
Your lymphatic system is a group of organs, vessels, and tissues that protect you from
infection and keep a healthy balance of fluids throughout your body.
41
what does your lymphatic system include?
o Lymph Vessels
o Lymph Nodes
o Tonsils
o Spleen
o Thymus
42
what are lymphatic vessels?
Lymphatic Vessels are a network of thin-walled vessels that transport excess interstitial fluid throughout the body, now called lymph.
43
what is lymph?
Lymph is a clear fluid that contains white blood cells, proteins, and cellular waste
products.
44
where are lymphatic vessels found?
throughout the body
45
what do lymphatic nodes do?
They act as filtration and immune surveillance sites.
46
what are lymphatic nodes?
Lymph nodes are small, bean-
shaped structures located along the lymphatic vessels.
47
what do lymphatic nodes contain?
Lymph nodes contain immune cells, such as lymphocytes and
macrophages, which help detect and fight infections
48
what are tonsils?
Tonsils are clusters of lymphoid tissue located at the back of the throat
49
what do tonsils do?
They help filter out and detect pathogens that may enter the body through the mouth or nose
50
what is your spleen?
The spleen is a large organ located under the ribcage on the left side of the abdomen
51
what does your spleen do?
It acts as a blood filter, removing damaged blood cells and pathogens from the
bloodstream
52
where is your thymus located?
The thymus is a gland located in the chest, behind the breastbone.
53
what are t cells?
T-lymphocytes (T-cells) destroy the body's own cells that have been taken over by viruses or become cancerous. They are made in the bone marrow and mature in the Thymus.
54
what is produced in bone marrow?
Bone marrow is where many white blood cells are produced.
55
what are b cells?
B-lymphocytes (B-cells) produce antibodies that are used to attack invading
bacteria, viruses, and toxins. They are made and mature in the Bone marrow.
56
where do lymphocytes travel?
Lymphocytes travel in our circulatory system & are concentrated in central lymph tissues and organs.
57
what are lymphocytes?
Lymphocytes are a type of white blood cell involved in the
specific (adaptive) immune response.
58
what do lymphocytes recognise?
They recognise antigens – unique proteins found on the
surface of pathogens.
59
how do lymphocytes respond to foreign antigens?
When lymphocytes detect antigens that are foreign (not naturally part of your body), some of them respond by producing antibodies. This process can take a few days, which is why you may feel sick during that time.
60
what do certain lymphocytes produce?
Certain lymphocytes can produce antitoxins to neutralise these harmful substances.
61
how does a helper t cell become activated?
When a Helper T-cell’s receptor binds to a complementary antigen presented by an
antigen-presenting cell, it becomes activated.
62
what does the helper t cell clone itself into?
1. Effector Helper T-cells
2. Memory Helper T-cells
63
what do the effector helper t cell do?
- Act immediately during the current infection.
- Release cytokines
- Usually die off once the infection is cleared.
64
what do the cytokines stimulate?
* B-cells to produce antibodies
* Cytotoxic T-cells to kill infected cells
* Phagocytes to increase their activity
65
what do the memory helper t cells do?
- Are long-lived and stay in the body after the infection.
- Do not actively secrete cytokines unless the same pathogen reappears.
- When reactivated, they quickly become effector cells again and respond faster than during the first infection.
66
HELPER T CELL DIAGRAM
67
how does a cytotoxic t cell become activated?
When a Cytotoxic T-cell’s receptor binds to a complementary antigen displayed on the
surface of an infected or abnormal body cell, and it receives signals from a Helper T-cell, it becomes activated
68
what does the cytotoxic t cell clone itself into?
1. Effector Cytotoxic T-cells
2. Memory Cytotoxic T-cells
69
what is the effector cytotoxic t cell?
- Act immediately during the current infection.
- Recognise and bind to infected or abnormal cells (e.g., virus-infected or cancerous cells).
- Kill infected cells
- Usually die off once the infection is cleared.
70
what release kills the infected cells?
* Perforin's – a protein that creates pores (holes) in the membrane of the infected cell.
* Granzymes – enzymes that enter the cell through the perforin-formed pores. These trigger apoptosis (programmed cell death).
71
what are memory cytotoxic cells?
- Are long-lived and stay in the body after the infection.
- Do not act unless the same pathogen reappears.
- When reactivated, they quickly become effector cells again and respond faster than during the first infection.
72
CYTOTOXIN T CELL DIAGRAM
73
how does a b cell become activated?
When a B-cell’s receptor binds to a complementary antigen (e.g., from a pathogen in the blood or lymph), and it receives a signal from a Helper T-cell, it becomes fully activated
74
what do the b cells clone itself into?
1. Plasma B-cells (Effector B-cells)
2. Memory B-cells
75
what are plasma b cells?
- Act immediately during the current infection.
- Produce large quantities of antibodies, which are highly specific to the original antigen.
76
what are memory b cells?
- Are long-lived and stay in the body after the infection.
o Do not produce antibodies unless the same antigen reappears.
- When reactivated, they quickly become plasma cells and produce antibodies faster and in greater numbers than during the first infection.
77
B CELL DIAGRAM
78
what is the specific adaptive immune system?
Only a B-cell with the
specific, complementary
receptor for an antigen will be activated.
79
what are antibodies?
Antibodies are proteins that attach to antigens on pathogens
80
what do antibodies do to fight infection?
They help fight infection by:
- Clumping pathogens together (agglutination)
- Marking pathogens for destruction by phagocytes
- Neutralising toxins (antitoxins)
81
ROLE OF ANTIGENS DIAGRAM
82
what happens after the infection is cleared?
- Some B-cells and T-cells
become Memory cells
- These stay in the body
and can respond much
faster if the same pathogen invades again
83
what is active immunity?
The type of immunity you get when your immune system makes its own antibodies after being stimulated by an antigen:
84
what is natural active immunity?
When you become immune after catching a disease (you have Memory B-Cells and Memory T-Cells)
85
what is artificial active immunity?
this is when you become immune after you’ve had a vaccination, containing a harmless dose of antigen
86
what is passive immunity?
you get immunity from being given antibodies made by a different organism. Your body doesn’t produce antibodies of its own
87
what is an example of natural passive immunity?
Baby gets antibodies from mother through the placenta and breastmilk
88
what is an example of artificial passive immunity?
injections containing antibodies from someone else (e.g., through blood donations – Tetanus antibodies can be injected)
89
active vs passive immunity worksheet answers
90
what are 4 ways vaccines help avoid this?
- Vaccines contain antigens that cause your body to produce memory cells against that antigen without causing disease.
- Vaccines protect the individual who received them, and because they reduce the occurrence of the disease, people NOT vaccinated are also less likely to catch it – this is called Herd Immunity.
- Vaccines can be injected or taken orally.
- Sometimes a booster might be needed later to make sure that the memory cells continue to be produced.
91
how long is the primary response for vaccines and why?
The primary response is slow, 10-14 days. It takes a while for the antigen to be recognised and the B-cells and T-cells to proliferate
92
what triggers the immune system to create memory T and B cells?
A vaccination introduces a harmless form of the
pathogen (or its antigen) into the body without causing disease. This triggers the immune system to create Memory B-cells and Memory T-cells specific to that antigen.
93
what is an endemic?
A disease that is regularly found at a steady level in a particular area or population
94
what is an outbreak?
A sudden increase in disease cases in a specific area above normal levels
95
what is an epidemic?
A rapid and large increase in disease cases in a community, region, or country.
96
what is a pandemic?
An epidemic that spreads across multiple countries or continents, affecting many people worldwide.
97
what did measles cause?
Measles caused serious illness, hospitalisations, and sometimes death, especially in young children
98
what is the measles cycle of symptons?
- Begins with a fever, cough, runny nose, and sore, red eyes, followed a few days later by a red, spotty, non-itchy rash and diarrhoea
- Complications such as diarrhoea, middle ear infection, and pneumonia occur in up to one- third of cases.
- Measles encephalitis is swelling of the brain caused by the measles virus and occurs in up to one in 1000 cases.
99
what is a fatal measles impact?
A fatal condition known as sub-acute sclerosing pan encephalitis occurs in one in 10000 cases and is a progressive neurological disorder that presents years after measles infection .
100
when was the measles vaccine introduced?
The measles vaccine was introduced in Australia in 1966
101
how are people at risk to measles?
People are at risk of measles if they are exposed to an infectious case and have never had measles, or if they have not received two doses of the measles-containing vaccine
102
what was smallpox?
Smallpox was an acute, highly infectious disease caused by the variola virus and transmitted by direct contact.
103
what percentage of victims did smallpox kill?
Smallpox killed between 12% – 30% of its victims.
104
who and when was the first vaccine made?
In 1798, Edward Jenner developed the world’s first vaccine.
105
what is polio caused by?
Polio is a highly infectious disease caused by the virus “poliovirus”.
106
what does polio do?
It invades the nervous system and can cause total paralysis in a matter of hours.
107
how is polio transmitted?
The virus is transmitted by person-to-person spread mainly through the faecal-oral route or, less frequently, contaminated water or food.
108
where does the polio pathogen multiply?
The pathogen multiplies in the
intestine
109
what age does polio mainly affect?
Mainly affects children under 5 years of age.
110
what did jonas salk do?
Developing the first successful polio vaccine in the 1950s, which significantly reduced the incidence of poliomyelitis worldwide.
111
what is herd immunity?
Herd immunity is a form of indirect protection that applies only to contagious diseases.
112
how does herd immunity occur?
It occurs when a sufficient percentage of a population has become immune to an infection, whether through previous infections or vaccination, thereby reducing the likelihood of infection for individuals who lack immunity.
113
what did covid spread through?
1. Respiratory droplets when an infected person coughs, sneezes, talks, or breathes
2. Touching contaminated surfaces, then touching your eyes, nose, or mouth
114
what happened with polio in 1988?
In 1988, the World Health Assembly adopted a resolution for the worldwide eradication of polio.
115
what are the 2 countries polio remain in?
Afghanistan and pakistan
116
what are 7 reasons why the expected cases of a disease (based on models or predictions) might end up higher than the actual
reported cases?
1. Preventative Measures
2. Behavioural Changes
3. Natural Immunity
4. Overestimation in the Model
5. Seasonality or Environmental Factors
6. Effective Public Health Intervention
7. Reporting Differences
117
where was covid first identified?
First identified in Wuhan, China, in December 2019
118
when was covid declared a global pandemic?
Declared a global pandemic by the WHO on 11 March 2020.
119
what is covid caused by?
A virus called SARS-CoV-2
(Severe Acute Respiratory Syndrome Coronavirus 2)
120
what is a disease?
a condition that disrupts the normal rate of the body or mind
Z-Science S2 Yr 9
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