Microbiology 4 Flashcards

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1
Q

Innate immunity

A

body’s first line of defense
non-specific
provides instantaneous response

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2
Q

Adaptive (acquired) immunity

A

2nd line of defense
used when innate immunity fails
highly specific: developed after exposure
conferred by our immune system: antibody and cellular responses
has memory

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3
Q

External physical barriers

A

intact skin
mucous membranes and secretions
ciliated epithelial cells

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4
Q

Intact skin

A

provides impenetrable barrier to pathogens

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5
Q

Mucous membranes and secretions

A

in the GI, respiratory and urogenital tracts

trap pathogens

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6
Q

Cilliated epithelial cells

A

sweep mucous entrapped microbes out of the system

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7
Q

External chemical barriers

A

Enzymes

Digestive secretions

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8
Q

Enzymes

A

sweat, saliva and tears

contain lysozyme

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9
Q

Digestive secretions

A

stomach acid

chemically inactivates the pathogen

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10
Q

Internal defensive factors

A
phagocytosis
natural killer cells
inflammation 
fever
complement system
interferon
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11
Q

Phagocytosis

A

cellular defense

neutrophills, monocytes and macrophages eat virus infected cells

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12
Q

Phagocytosis processes

A

chemotaxis
adherence
ingestion
digestion

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13
Q

Phagocytosis: chemotaxis

A

movement of cells toward a chemical stimulus

Uses chemotactic chemicals and cytokines

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14
Q

Chemotactic chemicals

A

microbial products or damaged tissue cells that attract phagocytes

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15
Q

Cytokines

A

chemicals released by phagocytes that have diverse functions

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16
Q

Chemokines

A
a class of cytokine
attract phagocytes to the site of infection
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17
Q

Phagocytosis: adherance

A

the ability of the phagocyte to bind to molecules on the surface of the microbe
toll-like receptors on phagocyte recognize bacterial cell components
pathogens have anti-phagocytic capsule

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18
Q

Opsonization

A

the coating of microbes with serum proteins for optimal adherence of phagocytes
ex: antibodies or a complement protein

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19
Q

Phagocytosis: ingestion

A

phagocytes extend projections called pseudopods that engulf the microbe
once engulfed, the microbe is enclosed in the phagosome
enzymes pump protons into the phagosome and lower pH
hydrolytic enzymes are activated

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20
Q

Phagocytosis: digestion

A

phagosomes fuse with lysosomes to produce the phagolysosome

undigested material remains in the residual body of the lysosome and is excreted

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21
Q

Lysosome

A

digestive enzymes degrade microbes
defensins create holes in microbe membranes
oxidatively inactivate microbes by creating toxic oxygen “oxidative burst”

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22
Q

Natural Killer cells

A

cellular defense
produce non-specific lysis by apoptosis of cancer and virus infected cells
activity increased by interferon exposure
recognize surface glycoproteins on infected cells

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23
Q

NK cell process

A

secretion of cytotoxic proteins like perforin insert into plasma membrane of target cells and cause cell to burst “cytosis”

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24
Q

Inflammation

A

body’s response to colonization of damaged tissues by pathogens

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25
Q

Acute inflammation function

A

kill microbes
clear debris
repair tissue

26
Q

Processes of inflammation

A

Acute inflammation
Histamine release
Repair and regeneration

27
Q

Histamine release

A

causes capillaries to vasodilate and become more permeable

28
Q

Inflammation: phagocytes

A

die in the process of engulfing microbes and accumulate at the site of infection as pus
can lead to abscess formation

29
Q

Inflammation: repair and regeneration

A

fibroblasts and connective tissue replace the destroyed tissue

30
Q

Fever

A

systemic increase in body temperature

oral temperature over 100.5 F

31
Q

Fever: pyrogens

A

substances that act on the hypothalamus and can re-set the body’s thermostat to a higher than normal temperature

32
Q

Exogenous pyrogens

A

include exotoxins and endotoxins from infectious agents

33
Q

Endogenous pyrogens

A

in response to exogenous pyrogens
macrophages release cytokine IL-1, causes neurons to release prostoglandins
prostoglandins reset thermostat of hypothalamus to a higher temperature

34
Q

Fever benefits

A

slows pathogen growth
microbial enzymes or toxins may be inactivated
increases rate of chemical reactions
enhanced phagocytosis
increased antiviral interferon production
increased breakdown of lysosomes causing death of infected cells
person will rest allowing body to fight infection

35
Q

Interferon protein

A

Molecular defense
Infected cell produces interferon
Interferon binds to uninfected cells
Binding stimulates production of enzymes (AVPs)
AVPs digest mRNA and limit its translation

36
Q

Complement/complement system

A

A molecular defense
Refers to a set of 20 large regulatory proteins
Work as a cascade – set of reactions amplify effect

37
Q

Complement system function

A

Enhance phagocytosis by phagocytes
Lyse microbes
Generate peptide fragments that regulate inflammation and other immune responses

38
Q

Complement system pathways

A

classical pathway

alternative/properdin pathway

39
Q

Complement system classical pathway

A

Antibody-mediated
Initiated when antibody binds to antigen
see notes for more information

40
Q

Complement system Alternative/ Properdin pathway

A

Antibodies do not play a role
Activated by contact of complement proteins and polysaccharides
Not all complement proteins are required
see notes for more information

41
Q

Iron binding proteins

A

Transferrin
Lactoferrin
Hemoglobin
Siderophores

42
Q

Transferrin

A

protein present in blood plasma that binds iron (co-factor for enzymes)

43
Q

Lactoferrin

A

protein present in saliva, mucus, and milk that binds iron

44
Q

Siderophores

A

proteins created by pathogens, compete to take iron away from iron-binding proteins

45
Q

Hemoglobin

A

located in red blood cells

46
Q

Iron binding proteins: Other mechanisms for obtaining iron

A

S. pyogenes releases hemolysins that lyse red blood cells

47
Q

Antimicrobial peptides

A

Short peptides between 12 and 50 amino acids long
Broad spectrum of anti-microbial activities
Cells produce AMPs when Toll-like receptors bind chemicals in microbes

48
Q

Defensins

A

present in mucus and other fluids, kill pathogens by forming pores in their membranes

49
Q

Immunity

A

the ability of an organism to recognize and defend itself against infectious agents

50
Q

Adaptive immunity

A

ability of a host to mount a specific defense against an infectious agent
Conferred by our immune systems

51
Q

Active immunity

A

created by person’s own immune system

52
Q

Passive immunity

A

created when ready-made Abs are given

53
Q

Antigens

A

A substance that is recognized as foreign and toward which an immune response is mounted
Some are polysaccharides
Some are glycoproteins

54
Q

Large protein antigens

A

Have several epitopes or antigenic determinants [where Ab binds]

55
Q

Haptens

A

large protein antigen
low molecular weight substances that cannot cause formation of antibodies
can act as antigen when bound to larger molecules

56
Q

Lymphocytes

A

Produce the acquired immune response
originate from stem cells
develop in bone marrow

57
Q

B Lymphocytes

A

continue to develop & differentiate in bone marrow

-> B cells

58
Q

T lymphocytes

A

travel via blood to thymus where they differentiate -> Tcells

59
Q

Humoral immunity

A

carried out by antibodies in our blood
B cells secrete antibodies
Antibodies mark pathogens (ex. bacteria and viruses), more easily recognized by phagocytes
Most effective against foreign substances outside of cells

60
Q

Cell mediated immunity

A

carried out by T cells
Most effective against antigens embedded in cell membranes
Attack body cells infected with bacteria and viruses
T cells also stimulate B cells to produce Ab (play a role in humoral immunity)