Chapter 8 - Infection and Defects in Mechanisms of Defense Flashcards

1
Q

Communicability

A

ability to spread from one individual to others and cause disease

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2
Q

Infectivity

A

ability of a pathogen to invade and multiply in a host

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3
Q

Infectivity involves a_______, e_______, d_________

A

-attachment
-escape of phagocytes
-dissemination (spread)

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4
Q

Virulence

A

severity or harmfulness of a disease or poison

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5
Q

Toxigenicity

A

ability to produce toxins

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6
Q

What do toxins influence?

A

a pathogen’s virulence

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7
Q

Portal of Entry

A

route by which a pathogen infects the host

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8
Q

What are some mechanisms of portal of entry?

A

-direct contact
-inhalation
-ingestion
-animal or insect bite

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9
Q

Is the DNA in a prokaryote cell enclosed in a nucleus?

A

no, it only has a nucleoid

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10
Q

Are prokaryotes aerobic or anaerobic?

A

they can be either depending on the species

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11
Q

Are gram-positive or gram-negative bacteria more dangerous?

A

gram-negative due to their outer membrane and porin channels which make them more difficult to defeat

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12
Q

Staphylococcus aureus is a common n______ infection

A

nosocomial

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13
Q

Where are staphylococcus aureus housed as normal microbiota?

A

nasal passages and skin

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14
Q

S. aureus produces a protein that blocks…

A

compliment attack

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15
Q

How does S. aureus avoid innate immunity?

A

producing inhibitors that avoid recognition by the immune system

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16
Q

What enzyme does S. aureus resist when engulfed by a phagocyte? How?

A

resists Lysozyme by changing the chemistry of their cell walls

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17
Q

S. aureus resists the action of many of what kind of drugs?

A

antibiotics

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18
Q

Exotoxins are released from ____ the pathogen

A

inside

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19
Q

Endotoxins are released from ______ the pathogen.

A

outside, specifically the outer capsule

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20
Q

What are exotoxins?

A

enzymes that damage host cell plasma membranes or inactivate critical protein synthesis enzymes

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21
Q

What do endotoxins activate? What do they produce?

A

they activate the immune system and produce fever

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22
Q

Bacteremia and septicemia are a result of the failure of ______ _________

A

defense mechanisms

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23
Q

Bacteremia

A

presence of bacteria in the blood

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24
Q

Septicemia

A

growth of bacteria in the blood

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25
Q

What two systems that start with “C” are activated by endotoxins?

A

complement and clotting systems

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26
Q

Endotoxins increase capillary permeability which leads to…

A

large volumes of plasma leaking into surrounding tissue and thus HYPOTENSION

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27
Q

What is the most common cause of pain or distress in humans?

A

viral disease

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28
Q

Viruses must _____ the host cell to replicate

A

enter

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29
Q

What is the structure of a virus?

A

it is neither a eukaryote or prokaryote and is just DNA or RNA surrounded by a capsid or envelope

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30
Q

Viruses are self-limiting meaning…

A

they resolve spontaneously without treatment or intervention

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31
Q

How are viruses transmitted?

A

-aerosol
-blood
-sex
-vector (tick, mosquito, etc.)

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32
Q

Viruses have cytopathic effects meaning…

A

they cause damage to living cells

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33
Q

Viruses inhibit host cell DNA or RNA _______

A

synthesis

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34
Q

How do viruses kill cells?

A

release lysosomes into the cell

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35
Q

Viruses can cause the _____ of host cells into multicellular giant cells

A

fusion

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36
Q

Viruses can cause the alteration of host cell antigen properties causing the immune system to attack…

A

its own cells

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37
Q

Can viruses cause cancer?

A

yes, they can transform host cells into cancerous cells

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38
Q

Why do viruses need host cells to replicate?

A

need to use the host cell resources

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39
Q

What is influenza?

A

a highly contagious viral infection of the respiratory passages

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40
Q

Influenza has the ability to produce antigenic variation meaning…

A

ability to change viral antigen spikes yearly

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41
Q

Fungi

A

are large eukaryotes with thick, rigid cell walls

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42
Q

Why do fungi have the ability to resist penicillin?

A

penicillin is a fungus itself

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43
Q

Fungi can exist as _____, _____, or both

A

yeasts or mold

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44
Q

Yeasts are ____cellular

A

unicellular

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45
Q

Molds are _____cellular

A

multi

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46
Q

How do yeasts reproduce?

A

by simple division or budding

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47
Q

How do molds reproduce?

A

they have branching hyphae and form a mycelium (ie. ringworm)

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48
Q

Mycoses are diseases caused by ______

A

fungi

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49
Q

What are dermatophytes?

A

fungi that invade skin, hair, or nails

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50
Q

What are the diseases dermatophytes produce called?

A

“tineas” ie. tinea capitis (scalp)

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51
Q

Fungal infections adapt to the host environment by having wide t________ variations and requiring low levels of o______-

A

temperature; oxygen

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52
Q

A low count of what blood cell promotes fungal infections?

A

white-blood-cells

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53
Q

Which fungus is the most common cause of fungal infections?

A

Candida albicans, especially in cancer and transplant patients

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54
Q

Candida albicans is housed as normal microbiota in…

A

skin, GI tract, and the vagina

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55
Q

How might immunocompromised people be affected by Candida albicans?

A

it can result in a deep infection with high mortality rates

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56
Q

What is the death rate of disseminated (spread) cadidiasis?

A

30-40%

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57
Q

Parasites are ___cellular protozoa

A

unicellular

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58
Q

What are helminths?

A

large worms such as flukes, nematodes, tapeworms

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59
Q

How are parasites spread to humans?

A

vectors or ingestion of contaminated food or water

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60
Q

How do parasites damage tissue?

A

by toxins or the inflammatory/immune response

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61
Q

What is the virus that causes Malaria called?

A

plasmodium vivax

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62
Q

Where does the malaria infection occur?

A

red blood cells

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63
Q

Malaria results in anemia within __-__ hours

A

48-72 hours

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64
Q

What causes the symptoms of malaria (fever, chills, vomiting)?

A

cytokine release (TNF-a and IL-1)

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65
Q

What are antibiotics?

A

natural products of fungi or bacteria that affect the growth of specific microorganisms

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66
Q

Antimicrobials can be b_______ or b______

A

bactericidal or bacteriostatic

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67
Q

Bactericidal

A

agent that kills other microorganisms

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68
Q

Bacteriostatic

A

agent that inhibits growth of other microorganisms

69
Q

What two factors are causing a rise in antibiotic resistance?

A

-lack of compliance with regimen
-overuse

70
Q

Lack of compliance means…

A

not using the antibiotic for the prescribed duration

71
Q

What does lack of compliance result in?

A

the strongest microbes are left alive to repopulate with resistance to the antibiotic

72
Q

What does overuse of antibiotics lead to?

A

destruction of the normal microbiome to open space for more infectious and resistant pathogens

73
Q

What are vaccines?

A

biological preparation of weakened or inactivated pathogens

74
Q

How long does it take the adaptive immune system to respond to a pathogen?

A

2 weeks

75
Q

What does a vaccine do?

A

activates an adaptive response (2 weeks) against a non-viral pathogen

76
Q

What is the result of a vaccine?

A

when viral infection occurs, there is no 2 week delay because adaptive immunity is already prepared

77
Q

Can vaccines be mixtures of different pathogens?

A

yes ie. DTaP or MMR

78
Q

Herd immunity requires what % of the population to be immunized?

A

85%

79
Q

What is a toxoid?

A

a chemically altered pathogen toxin injected to allow the body to learn to defeat it (ie. Tetanus toxoid)

80
Q

Passive immunotherapy involves giving p_______ antibodies to a person

A

preformed

81
Q

Passive immunotherapy is becoming more the focus with the rise in antibiotic _______

A

resistance

82
Q

What is human immunoglobulin?

A

antibodies obtained from a pathogen survivor

83
Q

What causes primary (congenital) immunodeficiency?

A

genetic defect

84
Q

What causes secondary (acquired) immunodeficiency?

A

another illness (ie. cancer)

85
Q

Most primary immune deficiencies result from how many gene defects?

A

one

86
Q

Are primary immune deficiency mutations sporadic or inherited?

A

sporadic, the mutation occurs before birth

87
Q

Sporadic Gene Mutation

A

mutation that is not inherited by parents but can be passed on to the children of the person who acquired the disease via mutation

88
Q

When do the symptoms of a primary deficiency appear?

A

early OR late in life

89
Q

1 in ___ Canadians have a primary immune deficiency but __% of these cases are undiagnosed.

A

1 in 200; 70%

90
Q

How are primary immune deficiencies categorized?

A

based on what aspect of the immune system is defective (ie. B and T lymphocyte or antibody deficient)

91
Q

Combined Immune Deficiency

A

group of rare genetic disorders of the immune system (ie. SCID, DiGeorge, Hypogammaglobulinemia)

92
Q

Severe Combined Immunodeficiency (SCID) results from an underdeveloped ________

A

thymus

93
Q

What does the thymus do?

A

produces T cells

94
Q

What results from SCID?

A

absence of T cells (lymphocytes)

95
Q

DiGeorge syndrome results from a dysfunction of the ________ and ________ gland

A

thymus and parathyroid gland

96
Q

What is the result of DiGeorge syndrome?

A

-inadequate T cell production (thymus)
-plasma calcium management impaired (pt gland)

97
Q

Hypogammaglobulinemia results from a defect in __ cell maturation or function

A

B cells

98
Q

What is the result of Hypogammaglobulinemia?

A

low levels of circulating antibodies (immunoglobulins) in the blood

99
Q

Are primary or secondary immune deficiencies more common?

A

secondary

100
Q

Why are secondary immune deficiencies not as clinically relevant?

A

the degree of immune deficiency is usually minor

101
Q

What are some extreme secondary deficiencies?

A

AIDS or cancer

102
Q

How do you evaluate immunity?

A

complete blood count (CBC) with differential

103
Q

What is a complete blood count (CBC)?

A

the total number of RBC, WBC, and platelets in the blood

104
Q

What is ‘differential’?

A

the individual numbers of lymphocytes, monocytes, granulocytes

105
Q

Immunity Evaluation: Quantitative determination of ___________ of immunoglobulins

A

subpopulations

106
Q

What does ‘total complement assay’ measure?

A

the total number of complements (MAC) in blood

107
Q

Replacement Therapies for Immune Deficiencies: Stem Cell Transplant

A

taking stem cells from bone marrow or umbilical cord cells to improve immunity

108
Q

Stem cell transplant results are usually __(temporary/permanent)__

A

temporary

109
Q

Replacement Therapies for Immune Deficiencies: Mesenchymal Stem Cell (MSCs) Injection

A

uses undifferentiated stem cells in bone marrow that eventually undergo differentiation

110
Q

MSCs injections have strong immunosuppressive properties meaning…

A

they can stop a variety of immune functions as well

111
Q

Replacement Therapies for Immune Deficiencies: Gene Therapy

A

insertion of normal genes into defective genetic material which reconstitutes the immune system

112
Q

What do some gene therapy recipients develop?

A

leukemia

113
Q

What viral disease causes Acquired Immune Deficiency Syndrome (AIDS)?

A

Human Immunodeficiency Virus (HIV)

114
Q

What does HIV do?

A

depletes helper T cells necessary for T and B cell activation

115
Q

What is the result of HIV?

A

dysfunctional adaptive immune system that increases susceptibility to disease, AIDS

116
Q

____sexual activity is the most common transmission route for AIDS

A

heterosexual (M/f)

117
Q

Are more women or men infected by AIDS?

A

more than 50% are women

118
Q

How do children contract HIV from their mothers?

A

across placenta or by breastmilk

119
Q

Why has a HIV vaccine not been developed?

A

HIV has variable antigen and genetic properties

120
Q

What is the issue with the antibodies of people with HIV?

A

they have lots but they aren’t protective, meaning even vaccine antibodies may not function effectively

121
Q

Epidemiology

A

branch of medicine that deals with incidence, distribution, and control of disease

122
Q

What is anti-retroviral therapy (ART) and what is it used for?

A

a drug containing RNA rather than DNA (retroviral) used to treat HIV

123
Q

What does ART do?

A

uses a combination of entrance, reverse transcriptase, integrase, and protease inhibitors to stop HIV from reproducing in cells

124
Q

Is ART curative of HIV?

A

no, but it decreases mortality rate

125
Q

Hypersensitivity is an…

A

altered immunological response to an antigen that results in disease or damage to the host

126
Q

3 Types of Hypersensitivity

A
  1. allergy
  2. autoimmunity
  3. alloimmunity
127
Q

Allergy

A

effects of hypersensitivity to environmental antigens (ie. pollen, bee sting)

128
Q

Exogenous Antigens

A

environmental antigens found outside human cells

129
Q

Endogenous Antigens

A

antigens found within human cells

130
Q

What is autoimmunity?

A

a disturbance in immunological tolerance of self-antigens (immune system doesn’t recognize its own antigens)

131
Q

What are autoimmune diseases?

A

clinical disorders of autoimmunity

132
Q

What is alloimmunity?

A

an immune reaction to the tissue of another individual

133
Q

When do alloimmune reactions occur?

A

blood transfusions, transplants, pregnancy

134
Q

How are hypersensitivity reactions characterized?

A

by their immune mechanism (Type I, II, III, IV)

135
Q

What do we mean when saying “hypersensitivity mechanisms are interrelated”?

A

hypersensitive reactions usually include more than one type of immune mechanism

136
Q

Immediate Hypersensitivity Reaction

A

reaction occurs within minutes or hours (ie. Anaphylaxis)

137
Q

Anaphylaxis

A

the most rapid and severe immediate reaction that occurs within minutes

138
Q

Anaphylaxis symptoms

A

-pruritis: severe itching
-erythema: red patches on skin
-vomiting
-diarrhea
-difficulty breathing

139
Q

Delayed Hypersensitivity Reaction

A

reaction occurs after several hours, are at maximal several days later

140
Q

Type I Hypersensitivity = ___ mediated

A

IgE (+ products of mast cells - histamine)

141
Q

What is the most common hypersensitivity reaction?

A

Type I

142
Q

Type I occurs against ________ antigens, inducing an allergic reaction

A

environmental

143
Q

Step 1: Type I Reaction - Initial Exposure to Allergen

A

sensitization: IgE binds to mast cell receptors

144
Q

Step 2: Type I Reaction - Subsequent Exposure to Allergen

A

hypersensitive reaction: mast cells release cytokines (histamine)

145
Q

During a Type I reaction which tissues are most commonly affected? Why?

A

skin, GI tract, and pulmonary tract tissues that have lots of mast cells

146
Q

Atopic

A

individuals predisposed to developing allergies when they have parents with allergies

147
Q

If one parent has allergies, ___% of offspring will

A

40%

148
Q

If both parents have allergies, ____% of offspring will

A

80%

149
Q

Example of Type I hypersensitivity

A

Hay fever

150
Q

Type II (cytotoxic) Hypersensitivity = ______ specific

A

tissue

151
Q

What does Type II do?

A

antibody mediated destruction of healthy host cells

152
Q

Type II is a reaction against a _______ cell or tissue

A

specific

153
Q

Tissue-Specific Antigens

A

attach only on the plasma membranes of certain cells (ie. platelets)

154
Q

How many mechanisms of Type II exist?

A

5 - A, B, C, D, E

155
Q

Step 1 of Type II Reaction (for all 5 subtypes)

A

antibody bind to tissue-specific antigens

156
Q

Type II Mechanism A (hint: compliment)

A

cell is destroyed by antibodies and compliments (MAC ruptures cell wall)

157
Q

Type II Mechanism B (hint: eating)

A

cell is destroyed by phagocytosis via macrophage

158
Q

Type II Mechanism C (hint: neutrophil)

A

neutrophils produce toxic products (granules) that damage tissue

159
Q

Type II Mechanism D (hint: ADCC)

A

Antibody-Dependent Cell-mediated Cytotoxicity (ADCC) - IgG antibodies bind to antigens and attract NK cells to destroy cell

160
Q

Type II Mechanism E (hint: block)

A

mechanism doesn’t destroy the target cell but causes it to malfunction because the antibody binding blocks normal receptor functions

161
Q

Grave’s Disease is an example of Type II mechanism __

A

E

162
Q

Type II example

A

hemolysis in medication allergies

163
Q

Type III Hypersensitivity = _______ complex

A

immune

164
Q

What is formed in circulation during a type III reaction?

A

antigen-antibody immune complex

165
Q

Where is the antigen-antibody immune complex deposited in a type III rxn?

A

in vessel walls or extravascular tissue

166
Q

Gluten allergies are an example of a Type ___ reaction

A

III

167
Q

Type IV Hypersensitivity = ___ mediated

A

cell, specifically T cells (not ANTIBODIES)

168
Q

Mechanism of a Type IV reaction:

A

reaction activated T cells which activate macrophages to destroy tissues

169
Q

Type IV reaction examples

A

graft rejection, poison ivy, metals