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Microbiology > Chapter 16 Micro > Flashcards

Chapter 16 Micro Flashcards

1
Q

What is susceptibility?

A

Able to be productively infected

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2
Q

What is resistance?

A

Unable to allow a productive infection

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3
Q

What is immunity?

A

An active process that prevents establishment or progression of infection

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4
Q

What are direct types of immunity?

A

Innate, adaptive and 3rd line of defense

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5
Q

What is innate immunity?

A

Defenses against any pathogen, present at birth

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6
Q

What are examples of the first line of defense?

A

physical factors
chemical factors
normal microbiota

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7
Q

What is the second line of defense?

A

non-specific physiologic processes

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8
Q

What is adaptive immunity?

A

Specific resistance to a specific pathogen, develops over time

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9
Q

What is the 3rd line of defense?

A

Specialized lymphocytes T cells and B cells

Antibodies

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10
Q

What are physical factors for first line of defense?

A

skin, mucus, ciliary escalator, epiglottis, saliva, urine, vaginal secretions

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11
Q

What does skin do?

A

forms physical barrier to entrance of microbes

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12
Q

What is the epidermis?

A

consists of tightly packed cells with a thick layer of keratin-containing dead cells
dryness inhibits microbes
water-tightness blocks microbes
shedding removes microbe

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13
Q

What is the dermis?

A

inner layer, connective tissue

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14
Q

What is the mucus membrane?

A

are an epithelial layer lining the respiratory, gastrointestinal, urogenital, visual, and auditory systems. They inhibits the entry of many microbes, but not as effective as intact skin

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15
Q

What is mucus?

A

traps microbes in respiratory and GI tracts. It is secreted by, covers, and protects cells of the mucus membrane

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16
Q

What is the ciliary escalator?

A

Cilia is the surface projection on cells of the respiratory tract that move mucus and trapped microbes

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17
Q

What is the lacrimal apparatus?

A

Tears flow from lacrimal glands under eyelid to lacrimal canal

washing and dilution by tears keeps microbes from settling on eye surface

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18
Q

What is sebum?

A

the oily secretion of the sebaceous glands that are embedded in the skin.
Sebum is a complex mixture of lipids (many fatty acids and triglycerides) that have anti-microbial activity

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19
Q

What does a pH of 6 or lower inhibit?

A 
Bacteria and fungi! 
Gastric juice ph: 1.2-3.0 
Vaginal secretions ph: 3-5 
Skin pH: 3-5 
Saliva and urine contain urea which is bacteriostatic
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20
Q

What is a lysozyme?

A

Lysozyme is a small enzyme that attacks the peptidoglycan chains in the cell walls of bacteria, causing the cells to burst
*Flemming discovered lysozyme as antibiotic

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21
Q

What microorganism is responsible for peptic ulcers?

A

H.pylori

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22
Q

What does the second line of defense consist of?

A

hematopoietic cells, particularly phagocytic cells
inflammation
fever
more antimicrobial substances

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23
Q

What are hematopoietic cells and what is their role in the body?

A
  • RBC carry O2 and Co2
  • WBC function in immunity and injury
  • Travel by circulation
  • Move in and out of intestinal space
  • Develop from stem cell
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24
Q

Increase in white cell count leads to what?

A

Leukocytosis

25
Q

Decrease in white cell count is what?

A

Leukopenia

26
Q

What is the circulation of the lymphatic system?

A

blood plasma —> interstitial fluid —> lymph —> blood plasma

27
Q

Lymph ultimately flows where?

A

Toward the heart

28
Q

What are the components of the lymph system?

A

Lymphoid tissues, nodes and organs

29
Q

What are neutrophils?

A

live only a short time

predominate early in infections

30
Q

What are macrophages?

A

last up to several months

predominate later in infections

31
Q

What is phagocytosis?

A

Ingestion of microbes

or particles by a cell, performed by phagocytes

32
Q

What are the phases of phagocytosis?

A
  1. chemotaxis and adherence of pseudopod
  2. ingestion of target
  3. formation of phagocytic vesicle or phagosome
  4. fusion with a lysosome, forming phagolysosome
  5. digestion of target by digestive enzymes
  6. formation of residual body
  7. discharge of indigestible material
33
Q

What are toll like receptors?

A
  • TLRs are protein molecules on cell surfaces throughout the body
  • TLRs are how macrophage pseudopods adhere to bacteria
  • TLRs are “pattern recognition receptors,” that is, they recognize pathogen-associated molecular patterns, specific signatures in molecules in the extracellular space
  • TLRs that recognize bacterially-produced molecules (such as LPS, peptidoglycan, flagellin, dsRNA), and signal the immune system via cytokines (like TNF-alpha) that bacteria are present
34
Q

How do some microbes evade phagocytosis?

A 
-Inhibit adherence, m proteins and capsules 
Example: S. pyognes
-Kills phagocytes, leukocidins
Ex: S. aureus 
-Lyse phagocytes, membrane attack complex
Ex: L. monocytogens 
-Escape phagosome 
Ex: Shigella 
-Prevent phagosome lysosome fusion
Ex: HIV 
-Survive in pahgolysosome
EX: Coxiella burnetti
35
Q

What is the purpose of inflammation?

A

to destroy and remove the injurious agent
limit the agent’s effects by walling it off
to repair the damage

36
Q

What is inflammation?

A

confines and destroys microbes and initiates tissue repair

37
Q

Signs and symptoms of inflammation include:

A 
Redness
Swelling (edema)
Pain	
Heat
(Loss of function)
38
Q

What is the process of inflammation?

A
  • cells damaged by infection release histamine, prostoglandins, and other signaling molecules
  • blood clot and abscess form
  • vasodilation, increased vessel permeability
  • phagocytes (monocytes, neutrophils) migrate
  • margination: phagocytes stick to endothelium, the blood vessel cells
  • diapedesis: phagocytes squeeze between endothelial cells
  • phagocytosis
  • tissue repair, epidermis and dermis regenerate
39
Q

What signaling molecules are released by cell damage?

A

-Histamine, kinins, prostaglandins, leukotrienes

40
Q

Vasodilation…

A

triggered by signaling molecules results in the redness and heat we association with inflammation.

41
Q

What is acute inflammation?

A

lasts relatively short time

42
Q

What is chronic inflammation?

A

lasts years
accumulation of activated macrophages induces fibroblasts, which synthesize collagen fibers, resulting in fibrosis or scarring

43
Q

What is the function of fever?

A

Intensifies he effects of interferons, inhibits growth of some microbes and speeds up some body reactions that aid in repair

44
Q

What is fever and its mechanism of action?

A

Abnormally high body temperature
Hypothalamus normally set at 37°C
Gram-negative endotoxin cause phagocytes to release interleukin–1 (IL–1)
Hypothalamus releases prostaglandins that reset the hypothalamus to a high temperature
Body increases rate of metabolism and shivering which raise temperature
Vasodilation and sweating: Body temperature falls (crisis)

45
Q

What are the advantages of fever?

A
  • Increases transferrins
  • Increases IL–1 activity
  • Produces Interferon
46
Q

What are some disadvantages of fever?

A

Rapid heart beat (tachycardia)
Acidosis (low blood pH)
Dehydration
44–46°C (111°F) is fatal!

47
Q

What are some antimicrobial substances?

A

Complement system, interferons, iron binding proteins, AMPS

48
Q

What is the complement system?

A
  • increases is an enzyme cascade that damages bacterial plasma membranes, increases the ability of antibodies and phagocytic cells to clear microbes and debris, and promotes inflammation
  • *part of innate immune system but works w adaptive
49
Q

Describe the classical pathway of complement activation

A
  • C1 is activated by microbe-antibody complexes
  • C1 causes C2 to split into C2a + C2b
  • C1 causes C4 to split into C4a + C4b
  • C2a* combines with C4b, and together they split C3
  • C3a and C3b initiate the complement cascade
50
Q

Describe the complement cascade

A

-C3b
binds to microbe and enhances phagocytosis, a process called opsonization (enhances phagocytosis)
splits C5
-C5b, C6, C7, C8 and multiple C9 fragments form a membrane attack complex, which punches a hole in the microbe, causing lysis
-C3a and C5a bind to mast cells which release histamine and other signaling molecules
-C5a is a chemotactic factor, which attracts phagocytes to the infection site

51
Q

What are the effects of complement activation?

A
  • Opsonization or immune adherence, which enhances phagocytosis
  • Formation of membrane attack complex which leads to cytolysis (cell lysis)
  • Attraction of phagocytes to the infected area
52
Q

What is the alternative pathway of complement activation?

A
  • C3 combines with B,D and P factors on microbe surface

- Causes C3 to split into fragments C3a and C3b

53
Q

What is the lectin pathway of complement activation?

A
  • lectin binds to invading cell
  • bound lectin splits c2 and c4
  • c2a and c4b combine and activate c3
54
Q

What are capsules?

A

prevent complement activation

55
Q

What do some surface lipid carbs do?

A

prevent membrane attack complex (MAC) formation

56
Q

What do some bacterial enzymes digest?

A

C5a

(C5a peptidase), which inhibits the infiltration of neutrophils and macrophages to the infection site

57
Q

What is the role of iron in innate immunity?

A
  • siderophores are secreted bacterial proteins that sequester iron from their environment and allow the microbes to more easily take it up
  • animal hosts have iron binding proteins, such as transferrins, that transport and store iron
58
Q

What are antimicrobial peptides?

A 
extremely small proteins: 12-15 amino acids long
very diverse; more than 600 known
broad spectrum
not specific
lyse bacterial cells
inhibit cell wall synthesis
destroy RNA and DNA
59
Q

What are interferons?

A

Interferons are cytokines, signaling molecules between cells during an immune response
IFN-alpha and IFN-beta: Cause cells to produce antiviral proteins that inhibit viral replication
IFN-gamma: Causes neutrophils and macrophages
to phagocytize bacteria

Microbiology (7 decks)

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