Chapter 7 - Immunity Flashcards
- Pathogens - Non-Specific Defenses Against Diseases - Specific Defenses Against Diseases - Prevention and Treatment of Diseases
1
Q
What is a pathogen?
A
A disease-causing organism
2
Q
What are the four types of pathogens?
A
- Bacteria
- Viruses
- Fungi
- Animal Parasite
3
Q
What is bacteria?
A
Unicellular, prokaryotic organisms with a cell wall but lacking membrane-bound organelles and an organised nucleus. A singular bacteria is called bacterium.
4
Q
Compare the size of bacteria and viruses
A
Bacteria: Seen with a light microscope
Viruses: Seen with an electron microscope
5
Q
Compare the genetic make-up of bacteria and viruses
A
Bacteria: DNA in unicellular prokaryotic cell, contains cell membrane, cell wall, flagella and slime capsule.
Viruses: Can be DNA or RNA covered by a protein coat
6
Q
Compare the treatment of bacteria and viruses
A
Bacteria: Antibiotics.
Viruses: Antivirals
7
Q
Compare the replication of bacteria and viruses
A
Bacteria: Replication by binary fission.
Viruses: Obligate intracellular parasite (needs host cell)
8
Q
Compare the type of bacteria and viruses
A
Bacteria: Mostly harmless.
Viruses: Mostly pathogenic
9
Q
Where is the DNA in bacteria located?
A
As Bacteria lacks a nucleus, their DNA either floats freely in the cytoplasm or is in the form of circular plasmids
10
Q
What are plasmids?
A
In a bacteria cell, small circular strands of DNA distinct from the main bacteria genome; composed of only a few genes and able to replicate independently within cells
11
Q
How is bacteria classified?
A
By shape
12
Q
What is a prokaryotes?
A
A single-celled organism lacking a instinct nucleus or specialised organelles
13
Q
What are the roles of bacteria?
A
Majority of bacteria are non-pathogenic, meaning they are harmless to humans. Many bacteria are essential to life on Earth through their role in the decomposition of organic material and the cycling of elements. Some bacteria is used in industrial processes such as yoghurt and cheese production
14
Q
How does bacteria cause illness?
A
May produce toxins or induce an allergic response
15
Q
What are viruses?
A
Microscopic particle with genetic material in form of a molecule of either DNA or RNA (never both) that is surrounded by a coat of protein or lipid envelope
16
Q
What does obligate intracellular parasites mean?
A
The pathogen can not be grown outside a cell
17
Q
How do viruses infect an individual?
A
They infect a living cell and its DNA or RNA induces the cell to manufacture more virus particles. The virus particles are then able to leave the host cell to infect others. During this process the cells become damaged, changed or die
18
Q
Can viruses be killed?
A
No but antivirals can control the infection
19
Q
What are some examples of viral disease?
A
Chicken pox, measles, mumps, rubella and small pox
20
Q
What is a bacteriophage?
A
A virus that multiplies in bacterial cells causing the bacteria to die. Defined as ‘good’ viruses
21
Q
What do fungi sometimes attack?
A
Human tissue
22
Q
What can mold spores cause?
A
Mild to serious allergies
23
Q
What does fungi infect?
A
Skin and hair
24
Q
What are parasites?
A
Parasites are organisms which live in or on another living thing
25
What are parasites called that live outside of the body and what is an example of them?
Ectoparasite.
Example: Lice, scabies, ticks
26
What are parasites called that live inside of the body and what is an example of them?
Endoparasite.
Example: Protozoans, Tapeworms, flukes, ameoba
27
Are viruses living things?
No
28
How do viruses differ?
Depending on the type of cell they invade, therefore the symptoms shown relate to the tissue that is affected
29
What are the six ways that pathogens are transmitted?
1. Contact
2. Body Fluids
3. Droplets
4. Ingestion
5. Airborne
6. Vectors
30
Explain direct physical contact transmission and provide an example
EXPLANATION: Actually touching an infected person.
EXAMPLE: Skin infections, STI's
31
Explain indirect physical contact transmission and provide an example
EXPLANATION: Touching an object that has been touched by an infected individual
EXAMPLE: Plantar Warts, Conjuctivitis
32
Explain body fluid transmission and provide an example
EXPLANATION: Transfer of body fluids from one person to another. Body fluids include blood, semen and saliva. The transfer occurs when body fluid of infected individual comes into contact with another individuals mucous membranes (such as in the nose, mouth, throat and genitals) or bloodstream (such as a needle or a break in the skin)
EXAMPLE: human papillomavirus (HPV), hepatitis B and C
33
Explain droplets transmission and provide an example
EXPLANATION: Occurs when tiny drops of moisture containing pathogenic organisms are emitted by breathing, talking, sneezing or coughing. The droplets may then be breathed in by others or may settle on food or utensils to be later with food
EXAMPLE: Ebola, COVID-19, mumps, colds, influenza
34
Explain ingestion transmission and provide an example
EXPLANATION: Ingestion of food or drink contaminated with pathogens may result in disease
EXAMPLE: Dysentery, typhoid fever, salmonella
35
Explain airborne transmission and provide an example
EXPLANATION: When the moisture in exhaled droplets evaporates, many bacteria are killed, but viruses and some bacteria remain viable and can cause infection when inhaled. As these particles are lighter, they remain viable for greater distance then those transmitted by droplets. The bacteria and viruses survive as spores
EXAMPLE: Measles, Chickenpox
36
Explain vector transmission and provide an example
EXPLANATION: The transfer of pathogens by other animals such as insects, ticks, mosquitos or mites. Some vectors transfer the pathogens directly. Others (such as house flies) may spread the pathogen to food or water, which is then ingested. Many vector-borne diseases are spread by a specific vector
EXAMPLE: Malaria and dengue fever by mosquitos, trypanosomiasis by the tsetse fly, Lyme disease by ticks and the bubonic plague by fleas
37
What defence methods are involved in the first line of defence?
1. Respiratory System
2. Eyes
3. Ears
4. Mouth & gastrointestinal system
5. Skin, sweat & Sebaceous glands
6. Urinary system & reproductive system
38
Outline how skin acts as a defence method
- Physical Barrier
- Resident Bacteria
- Sweat (contains lysozyme)
- Sebum
- Shedding action
39
Outline how the respiratory system acts as a defence method
- Nasal Cavity (Contains hair, mucus, cilia and lysozymes)
- Reflexes (sneezing)
- Trachea (Contains cilia and mucus)
40
Outline how the eyes acts as a defence method
- Tears (flushing action, contains lysozymes and salts)
- Reflexes (crying, blinking)
- Eyelashes/eyebrows
41
Outline how the ears acts as a defence method
- Contain cerumen which is though to repel insects and inhibit bacterial growth
42
Outline how the gastrointestinal system acts as a defence method
- Saliva contains lysozyme
- Gastric juices are highly acidic
- Sticky mucus lining stops micro-organisms from establishing
- Mucus in the anus traps pathogens
43
Outline how the urinogenital acts as a defence method
- Flushing action
- Resident bacteria
- Low ph = high acidity
44
What is lysozyme and where can it be found?
EXPLANATION: powerful anti-microbial enzyme
LOCATION: Bodily secretions such as saliva, tears and sweat
45
What is a reflex?
A reflex is an automatic, involuntary response to a stimulus. Protective reflexes help to protect the body from injury
46
What are the four protective reflexes?
1. Sneezing
2. Coughing
3. Vomiting
4. Diarrhoea
47
What is the stimulus for sneezing?
Irritation of the walls of the nasal cavity caused by Noxious fumes or dust particles, which are likely to be carrying micro-organisms
48
What is the stimulus for coughing?
Irritation in the lower respiratory tract – the bronchi and the bronchioles
49
What is the stimulus for vomiting?
Psychologically, excessive stretching of the stomach and bacterial toxins
50
What is the stimulus for diarrhoea?
Irritation of the small and large intestines caused by Bacteria, Viruses, Protozoans
51
What is the process of sneezing?
Forceful expulsions of air from the lungs carries mucus, foreign particles and irritating gases out through the nose and mouth
52
What is the process of coughing?
Air is forced from the lungs to try remove the irritant. The air drives mucus and the foreign matter up the trachea towards the throat and mouth
53
What is the process of vomiting?
Contraction of the muscles of the abdomen and the diaphragm, (not the contraction of the stomach), expels the stomach contents
54
What is the process of diarrhoea?
The irritation causes increased contractions of the muscles of the wall of the intestines so that the irritant is removed as quickly as possible. Material does not stay in the large intestine long enough for water to be absorbed, so the faeces are very watery
55
What are the four defence methods involved in the second line of defence?
1. Inflammation
2. Fever
3. Phagocytosis
4. Lymphatic System
56
What is inflammation?
A response to any mechanical or chemical damage to the tissue (can be an infection)
57
What do words ending in -itis indicate
Inflammation of specific organs or tissues
58
What is the purpose of inflammation?
1. Reduce the spread of any pathogens, to destroy them and to prevent the entry of additional pathogens
2. Remove damaged tissue and cell debris
3. Begin repair of the damaged tissue
59
What are the four main symptoms of inflammation?
1. Redness (More blood going to area)
2. Swelling (More fluid to decrease spread of pathogen)
3. Heat (WBC's working overtime)
4. Pain (prevent further damage)
60
What are MAST cells?
A type of WBC's that detect damage to the skin barrier
61
What do MAST cells secret?
1. Histamines
2. Heparin
3. Cytokines
62
What effects does histamine have?
1. Blood vessels dialate
2. Vessels become more permeable which allows plasma to escape into teh tissue
63
What effects does heparin have?
1. Prevents clotting to immediate area of injury
2. Restricts pathogen movement
3. Localises WBC's activity
64
What effect does cytokines have?
1. Increases phagocytosis
2. Increases number of macrophages
65
Outline the inflammatory response
1. Tissue is damaged
2. Chemicals including heparins and histamines are released by the MAST cells
3. Local blood vessels dialate and become more permeable (Histamines)
4. Fluid in tissues is increased
5. Defensive chemicals and cells move to the damaged tissue
6. Phagocytosis by WBC's of pathogens and damaged tissue (pus may form)
7. New cells are produced by mitosis to replace teh damaged ones
66
What is a fever?
Elevated body temperature
67
What causes a fever?
A fever is the result of a resetting of the bodies thermostat, controlled by the hypothalamus, to a higher level than usual. This reaction is thought to be due to chemicals called pyrogens that are released by white blood cells during the inflammatory response and act on the hypothalamus
68
What are pyrogens?
Chemicals that are released by white blood cells during the inflammatory response and act on the hypothalamus to reset the bodies thermostat. They are fever induced substances
69
What is an example of a pyrogen?
interleukin-1
70
What is the purpose of a fever?
Creates an unfavourable environment that:
1. Speeds up chemical reactions (quicker repair)
2. Inhibits pathogen spread/growth
3. Enhances interferon activity which decreases viral replication
71
When a person has a fever, is the body temperature still regulated?
When a person has a fever, the body temperature is still regulated in response to heat or cold, but the set point is at a higher level
72
What is the process of a fever?
1. Macrophages (WBC's) encounter a pathogen and releases pyrogens
2. Pyrogens stimulate/act on the hypothalamus to 'reset'/increase its thermostat to a higher temperature
3. Hypothalamus responds by shivering and vasoconstricting the blood vessels in the skin
4. Eventually the fever breaks at the crisis point, sweating and vasodilation of the blood vessesl in the skin takes place
73
How does the hypothalamus respond to pyrogens?
1. Makes the skeletal muscles shiver (increases heat production)
2. Vasoconsticts the blood vessels in the skin (decreases heat loss)
3. Adrenaline is released
74
How does the body temperature lower after the fever breaks?
1. Blood vessels in the skin vasodilate (increases heat loss)
2. Sweating occurs (increases heat loss)
75
What happens if the body temperature goes to high?
If the body temperature goes too high it can cause convulsions and brain damage
76
What body temperature is defined as dangerous?
Generally, death will result if the body temperature reaches 44.4-45.5 degrees Celsius
77
What are the three main types of phagocytic cells?
1. Monocytes and Macrophages
2. Neutrophils
3. Dendritic Cells
78
What are phagocytes?
Specialised white blood cells (WBC's) or leucocytes, that engulf and digest micro-organisms and cell debris. Phagocytes eliminate many pathogens before an infection has had a chance to take hold
79
What do monocytes and macrophages do when acting as a non-specific defence method?
1. When a tissue becomes infected or inflamed, monocytes leave the bloodstream and enter the tissue
2. In the tissue, monocytes differentiate into macrophages which are large phagocytic cells
3. Some macrophages move through the tissues looking for and destroying pathogens and others are in a fixed position and only deal with the pathogens that come to them
Macrophages are particularly important in removing microbes and dying cells through phagocytosis
80
What do neutophils do when acting as a non-specific defence method?
1. During an infection , neutrophils are the first cells to move into the tissue to destroy the pathogens by phagocytosis.
They are particularly important in killing pathogens inside the cells
81
What are neutophils?
- Neutrophils are described as a granulated leucocyte, due to the granules visible in their cytoplasm
- They are also characterised by their lobulated nucleus
- Neutrophils are the abundant leucocyte (55%-70% of all leucocytes)
- They have short life spans and die after a few days
- The dead cells make up a large portion of the pus that forms after an infection
82
What do dendritic cells do when acting as a non-specific defence method?
These cells have the ability to detect, engulf and process foreign particles.
They then use information about the ingested particles to assist with specific immunity
83
What are dendritic cells characterised by?
Dendritic cells are characterised by projections from the cytoplasm
84
What are the three main traits of a phagocyte?
1. Mobile, specialised WBC's
2. Can engulf and destroy microbes of cellulatr material
3. Recognise microbes as 'non-self', engulf and then digest
85
What does the lymphatic system consist of?
- A network of lymph capillaries joined to larger lymph vessels
- Lymph nodes, which are located along the length of some lymph vessels
86
What are the main functions of the lymphatic system?
- Collect some of the fluid that escapes from the blood capillaries and return it to the capillary system
- Internal defence against pathogenic organisms
87
What is the process of the lymphatic system in non-specific defences?
- Lymph entering the lymph nodes contains cell debris, foreign particles and micro-organisms may be pathogenic and, if not destroyed, could cause disease
- Larger particles, such as bacteria are trapped in the meshwork of fibres as the lymph flows through the spaces in the nodes
- Macrophages ingest and destroy these particles by phagocytosis
- When infection occurs, the formation of lymphocytes increases, and the lymph nodes become swollen and sore
- Most lymphocytes are important in the specific immune system response to a particular pathogen
88
Define immunity
The ability of the body to fight infection and/or foreign invaders by producing antibodies or killing infected cells
89
Define immune responses
When foreign particles/organisms penetrate the non-specific defences, the body reacts by producing special cells from the lymphoid tissue
90
What are the two main lymphocytes involved in the immune response?
1. B-cells
2. T-cells
91
Where are B-cells and T-cells produced?
Bone marrow
92
Where do B-cells and T-cells mature?
B-cells: Bone marrow
T-cells: Thymus
93
Where do B-cells and T-cells end up?
In the lymphoid tissue
94
What are the two parts of the immune response?
1. Antibody-Mediated Immunity (Humoral)
2. Cellular-Mediated Immunity (Cellular)
95
What is involved in antibody-mediated immunity?
B-cells (attack) and antibodies
96
What is involved in cellular-mediated immunity?
T-cells (destroy)
97
When does antibody-mediated immunity occur?
Resistance before micro-organisms or substances enter a cell
98
When does cell-mediated immunity occur?
Resistance at the intracellular phase of infection
99
What is 'immunological competence' and who acquires it?
Matured B-cells and T-cells aquire it. It mean that they are able to identify chemical markers called antigens that distinguish self from non-self cells and specifici pathogens that cause diseases
100
What triggers an immune response?
Antigens (specifically non-self antigens)
101
What are antigens?
Large molecules that may be a protein, polysaccharide (carbohydrate), nucleo-protein (nucleic acids) or a glycolipid (lipid)
102
When does the immune system distinguish between 'self' and 'non-self' antigens?
The immune system become programmed before birth to distinguish between 'self' and 'non-self' antigens
103
What are antigen-presenting cells?
Phagocytic cells that digest pathogens and present the non-self antigen to lymphocytes
104
What is an example of an antigen-presenting cell?
Typically macrophages but also can be dendritic cells and undifferentiated B-cells
105
What is an antibody?
A specialised protein made in response to non-self antigens?
106
What shape are antibodies?
Y-shaped
107
What group of proteins do antibodies belong to?
Immunoglobulins (Ig)
108
What is the function of antibodes?
They combine with teh non-self antigen to form an 'antigen-antibody complex'
109
Are antibodies specific?
Antibodies are specific
- Antigen molecules have specific active sites with a particular shape.
- The antibody has a complementary shape
- This allows the two molecules to fit together like a 'key and lock'
- Each antibody can combine with only one particular antigen
110
What are the six ways that Antigen-Antibody binding is removed?
'CAPDIN'
1. Coats Bacteria
2. Agglutination
3. Precipitation
4. Dissolves organisms
5. Inactivates
6. Neutralisation of antigen
111
Explain 'C' in 'CAPDIN'
Coats Bacteria:
Antibody binds to a bacteria cell so they are easily consumed, promoting phagocytosis
112
Explain 'A' in 'CAPDIN'
Agglutination:
Clumping of bacteria, viruses or foreign blood cells by antibodies, making antigens easier to be phagocytised
113
Explain 'D' in 'CAPDIN'
Dissolves Organisms
114
Explain 'I' in 'CAPDIN'
Inactivates:
Antibody combines with foreign enzyme/bacterial toxin or inactivates them by inhibiting reactions with other cells or compounds
115
Explain 'N' in 'CAPDIN'
Neutralisation of an Antigen:
Antibodies bind to viruses or toxins, preventing them from entering host cells
116
Outline the process of Antibody-Mediated Immunity
1. Antigen-presenting cells recognise, engulf and digest pathogens, displaying the antigen on their surface
2. Antigen-presenting cells reach lymphoid tissue and present the antigens to lymphocytes
3. Antigen-presenting cell (usually a macrophage) presents the cell to either a Helper T-cell (a) or a B-cell (b)
4. a) The helper T-cell releases cytokines which act as a messenger that activates the B-cells
5. b) The B-cells which are located in the lymph tissue detect the 'non-self' antigen
6. Specific B-lymphocytes are stimulated to undergo rapid cell division
7. Most new B-cells develop into plasma cells, which produce antibodies and release then into the blood and lymph
8. Antibodies combine with the specific antigen and inactivate or destroy it
9. Some of the new B-cells form memory cells
117
What pathogens does Humoral immunity work against?
- Bacteria
- Toxins
- Viruses
- Red blood cells of a different blood group
118
What do B-cells differentiate into?
Memory Cells and Plasma Cells (secrete specific antibodies)
119
What pathogens does cellular immunity work against?
- Transplanted tissues and organs
- Cancer cells
- Cells that have been infected by viruses or bacteria
- Fungi and Parasites
120
What do T-cells differentiate into?
- Memory Cells
- Killer T-cells
- Helper T-cells
- Suppressor T-cells
121
Outline the process of Cell-Mediated Immunity
1. Antigen-presenting cells recognise, engulf and digest pathogens, displaying the antigen on their surface
2. Antigen-presenting cells reach lymphoid tissue and present the antigens to lymphocytes
3. Helper T-cells are stimulated by antigen-presenting cells, which release cytokines
4. Specific T-lymphocytes are stimulated to undergo rapid cell division
5. Most new T-cells develop into killer T-cells or helper T-cells, which migrate to the site of infection
6. Killer T-cells destroy the antigen, while helper T-cells promote phagocytosis by macrophages
7. Some sensitised T-cells form memory cells
122
What are the three types of functioning T-cells?
1. Helper T-cells
2. Killer T-cells (also known as cytotoxic T-cells)
3. Supressor T-cells
123
Do T-cells respond to free antigens?
No, only cell-bound antigens
124
Describe the function of Killer T-cells
Leave the lymph node and migrate to the site of infection and deal with the invading antigen by:
1. Lysing (puncturing) them
2. Attracting macrophages and stimulating them into a 'feeding frenzy' (Increases phagocytosis)
3. Secretes cytokines to activate other lymphocytes
125
Describe the function of Helper T-cells
Play an important role in both humoral and cellular immunity.
They bind to the antigen on antigen-presenting cells, stimulating the secretion of cytokines that:
a) Attract lymphocytes to the infection site which becomes sensitised and activated, thus intensifying the response
b) Attract macrophages to the place of infection so that the macrophages can destroy the antigens by phagocytosis
c) Intensifying the phagocytic activity of macrophages
d Promote/activates the action of killer T-cells and B-cells
126
Describe the function of Suppressor T-cells
Act when the immune system activity becomes excessive or the infection has been dealt with successfully
They release substances that inhibit/regulate T-cell and B-cell activity, slowing down the immune response to stop them from causing excessive immune reations that might be severely damaging to the body. Ensures the antigen is tolerated by the body
127
What is a primary response?
- Immune systems first exposure to an antigen
- Body usually responds fairly slowly
- Often takes several days to build up large amounts of antibodies
- Slow response is due to it taking time for the B-cells to multiply and differentiate into plasma cells and then secrete antibodies
- Once the level of antibodies reaches a peak, it begins to decline
- The primary response leaves the immune system with a memory of that particular antigen
128
What is a secondary response?
- Second or subsequent exposure to the same antigen
- Response is much faster due to memory cells recognising the antigen more quickly
- Plasma cells are able to form very quickly, with antibody levels in the blood plasma rising rapidly to a higher level that lasts longer
- Occurs so quickly that the antigen has little opportunity to exert any noticeable effect on the body and no illness results
129
What are the two ways immunity can be acquired?
- Naturally
- Artificially
130
Explain natural immunity
Immunity that occurs without any human intervention, the individual comes into contact with the antigen
131
Explain artificial immunity
Immunity that results from giving people an antibody or antigen
132
What is naturally occuring ACTIVE immunity?
When a person gets antigens and manufactures their own antibodies as a result of an antigen attack (Builds own immune response)
133
What is artificially occuring ACTIVE immunity?
When a person recieves antigens in the form of a vaccine and manufactures their own antibodies
134
What is natutrally occuring PASSIVE immunity?
When a person recieves the antibodies from the mother as they are passed across the placenta to a developing foetus or when the mothers antibodies are passed to the baby in breast milk
135
What is artificially occuring PASSIVE immunity?
When a person recieves the antibodies from another person usually by transplant/injection into the bloodstream
136
What does immunisation mean?
Programming the immune system so that the body can respond rapidly to infecting micro-organisms (developping immunity)
137
What is a vaccination?
The artificial introduction of antigens of pathogenic organisms so that the ability to produce the appropriate antibodies is acquired without the person having to suffer the disease
138
What are the four types of vaccines?
1. Live Attenuated
2. Inactivated
3. Toxoid
4. Sub-unit
139
What are live attenuated vaccines?
Vaccines that contain living attenuated micro-organisms of reduced virulence (disease-producing power of a micro-organisms). Therefore, the immunised person does not contract the disease but manufactures antibodies against the antigen
140
What are inactivated vaccines?
Vaccines that contains dead micro-organisms. Produce an immunity that is shorter lasting than immunisation using live attenuated micro-organisms
141
What are toxoid vaccines?
In cases where bacteria produce their effects in humans by liberating toxins, it is not necessary to use bacteria for immunisation. The toxins produced by the bacteria can be inactivated (called toxoids), so that when they are injected into someone, they do not make the person ill
142
What are sub-unit vaccines?
Instead of using a whole dead or attenuated micro-organism, a fragment of the organism can be used to provoke the immune response
143
What do live attenuated vaccines provide immunisation against?
* Polio
* Tuberculosis
* Rubella
* Measles
* Mumps
* Yellow fever
144
What do inactivated vaccines provide immunisation against?
* Cholera
* Typhoid
* Whooping Cough
145
What do toxoid vaccines provide immunisation against?
* Diphtheria
* Tetanus
146
What do sub-unit vaccines provide immunisation against?
* HPV
* Hepatitis B
147
What is herd immunity?
A type of group immunity that occurs when such a high percentage of people in a population are immunised that those who are not immunised are protected. To achieve herd immunity large scale vaccination programs need to be completed.
148
Outline the two health related factors that may affect a person's viewpoint on vaccines
1. Allergic Reactions: Individual may be allergic to the vaccine or the medium used to inject the vaccine
2. Preservatives: Most vaccines contain chemicals that act as preservatives that some may believe affect the CNS
149
Outline the social factors that may affect a person's viewpoint on vaccines
1. Ethical Concerns with the use of animals to produce vaccines
2. Ethical Concerns with the use of human tissue to produce vaccines
3. Ethical Concerns with informed consent
4. Ethical Concerns with testing on animals
5. Concerns about promoting secual activity in teenagers
6. Availability of vaccines
150
Outline the cultural factors that may affect a person's viewpoint on vaccines
Religious Beliefs: A few religiions are opposed to vaccines as they rely on faith healing or healing through prayer, meaning vaccines cotradict their religious beliefs
151
Outline the economic factors that may affect a person's viewpoint on vaccines
1. Cost of vaccine: May be too expensive for some people to afford
2. Commercialism: The interests of commercial vaccine production may affect its use
152
What are antibiotics?
Drugs that are used to fight infections of micro-organisms, particularly bacteria.
153
What do antibiotics treat?
Bacterial Infections
154
What are the two types of antibiotics based on actions?
1. Bacteriocidal
2. Bacteriostatic
155
Explain the function of Bacteriocidal antibiotics
Kills bacteria by altering the membrane or cell wall structure, or by interfering with protein synthesis. They target the outer cell walls, inner cell membranes or metabolic pathways of bacteria
156
Explain the function of Bacteriostatic antibiotics
Prevents the reproduction of bacteria, mainly by interfering with protein synthesis. (DO NOT kill bacteria). By inhibiting the bacteria’s growth, the individual’s immune system is then able to overcome the infection
157
Provide an example of a bacteriocidal antibiotic
Penicillin and Polymyxins
158
Provide an example of a bacteriostatic antibiotic
Tetracyclines, chloramphenicol, macrolides and spectinomycin
159
What are the two types of antibiotics based on what bacteria they treat?
1. Broad-spectrum
2. Narrow-spectrum
160
What do broad-spectrum antibiotics treat?
Used and effective against a wide range of different types of bacteria
161
What do narrow-spectrum antibiotics treat?
Only used and effective against specific type of bacteria, they target disease causing bacteria
162
What is multiple drug resistance?
When some strains of bacteria have built up resistance to most of the available antibiotics. Bacteria that have developed multiple drug resistance are commonly referred to a ‘super bugs’
163
What is total drug resistance?
When some strains of bacteria have complete resistance to all types of antibiotics
164
What is antibiotic resistance?
A bacteria’s ability to resist the effect of antibiotics
165
How has antibiotic resistance occured?
Occurs when bacteria evolves and changes, building a resistance to the antibiotics that are used to treat the infection that the specific strain of bacteria causes. The antibiotics is then unable to kill the bacteria or inhibit their growth, making them ineffective. As the amount of antibiotics used to treat infections increases, antibiotic resistance also increases. Therefore, the overuse of antibiotics has resulted in multiple drug resistance. Antibiotic resistance is naturally occurring but has been accelerated by the misuse of antibiotics. Natural selection is a major factor that has resulted in antibiotic resistance
166
What are antivirals?
Drugs used specifically for treating viral infections.
167
What is the function of antivirals?
To inhibit viral replication
168
What must viruses do before they replicate?
Enter a host cell
169
How do antivirals work?
1. Prevent entry
2. Prevent virus releasing DNA or RNA into host cell nucleus
3. Prevent it slicing into genetic material into the host cell DNA
170
What are some examples of diseases that can be treated by antivirals?
Tamiflu, Acyclovir (herpes ‘cold sores’), hepatitis B and C, influenza A and B, Zidovudine (AZT) for HIV
171
How do bacteria differ in their actions to viruses?
Bacteria can self replicate as they contain a nucleus whereas viruses need a host cell to replicate
172
Provide examples of when a Humoral response would be more important
1. A blood transfusion
2. Tetanus toxins
3. A bacterial skin infection
173
Provide examples of when a Cellular response would be more important
1. A heart transplant
2. A viral infection
3. A fungal infection
174
Provide an example of when someone would recieve natural active immunity
When an individual has the disease and recovers from it
175
Provide an example of when someone would recieve natural passive immunity
When antibodies enter the bloodstream across the placenta or in breast milk
176
Provide an example of when someone would recieve artificial active immunity
When and individual has the ability to manufacture antibodies results from being given an antigen by vaccination
177
Provide an example of when someone would recieve artificial passive immunity
When a person is injected with antibodies to combat a particular infection, commonly done when a person is exposed to pathogens that cause serious diseases, such as tetanus, diphtheria and rabies
178
How do vaccines work?
They imitate an infection to engage the body's natural defenses to prepare the body with memory cells if they are to be infected by that specific antigen
179
Why is it difficuly to produce vaccines for viral infections?
The viruses have already changed their format by the time vaccines are developed
180
What is the function of a 'booster shot', why are they neccesary?
To maintain the high levels of antibodies needed to provide immunity
181
Define virulence
The disease-producing power of a micro-organisms
182
Define attenuated
Weakened or thinned
183
What is a toxoid?
An inactivated form of a bacterias toxin
