Ch. 20 - Part 1 Flashcards

1
Q

immune system

A

provides resistance to disease

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2
Q

immune system two intrinsic systems

A

innate (nonspecific) & adaptive (specific)

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3
Q

first line of defense

A

external body membranes (skin and mucosae)

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4
Q

second line of defense

A

antimicrobial proteins, phagocytes, and other cells (inhibit spread of invaders; inflammation most important mechanism)

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5
Q

third line of defense

A

attack particular foreign substances (takes longer to react than innate)

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6
Q

pathogens

A

disease-causing microorganisms

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7
Q

surface barriers are skin and mucous membranes, along with their secretions

A

physical barrier to most microorganisms; keratin is resistant to weak acids and bases, bacterial enzymes, and toxins; mucosae provide similar mechanical barriers

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8
Q

protective chemicals of the skin and mucous membranes

A

acid, enzymes

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9
Q

acid mantle

A

acidity of skin and some mucous secretions inhibits growth

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10
Q

enzymes

A

lysozyme of saliva, respiratory mucus, and lacrimal fluid kills many microorganism; enzymes in stomach kill many microorganisms

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11
Q

mucin

A

sticky mucus that lines digestive and respiratory tract traps microorganisms

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12
Q

defensins

A

antimicrobial peptides that inhibit microbial growth

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13
Q

other chemicals

A

lipids in sebum and dermcidin in sweat are toxic to some bacteria

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14
Q

respiratory system also has modifications to stop pathogens

A

mucus-coated hairs in nose trap inhaled particles; cilia of upper respiratory tract sweep dust-and bacteria –> laden mucus toward mouth

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15
Q

innate system necessary if microorganisms invade deeper tissues; includes:

A

phagocytes, natural killer (NK) cells, inflammatory response, antimicrobial proteins, fever

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16
Q

pattern recognition receptors

A

found in second-line cells; recognize and bind tightly to structures on microbes, disarming them before they do harm

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17
Q

Toll-like receptors (TLRs)

A

plays central role in triggering immune responses; human have 11 different ones and each recognizes a particular class of attaching microbe

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18
Q

phagocytes

A

white blood cells that ingest and digest (eat) foreign invaders

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19
Q

neutrophils

A

most abundant phagocytes, but die fighting; become phagocytic on exposure on infectious material

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20
Q

macropahges

A

develop from monocytes and are chief phagocytic cells

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21
Q

free macrophages

A

wander through tissue spaces; ex –> alveolar macrophages

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22
Q

fixed macrophages

A

permanent residents of some organs; ex –> stellate macrophages (liver) and microglia (brain)

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23
Q

opsonization

A

immune system uses antibodies or complement proteins as opsonins that coat pathogen

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24
Q

Phagocytosis

A

(1) phagocyte recognizes and adheres to pathogen’s carb “signature”; (2) cytoplasmic extensions (pseudopods) bond to and engulf particle in vesicle called phagosome; (3) phagosome fuses with lysosome, forming phagolysosome; (4) phagolysosome is acidified, and lysosomal enzymes digest particles; (5) indigestible and residual waste is exocytosed from phagocyte

25
Q

respiratory burst

A

kills pathogens resistant to lysosomal enzymes by: releasing cell-killing free radicals, producing oxidizing chemicals, increasing pH and osmolarity of phagolysosome

26
Q

Benefits of inflammation

A

prevents spread of damaging agents, disposes of cell debris and pathogens, alerts adaptive immune system, sets the stage for repair

27
Q

Four cardinal signs of acute inflammation

A

redness, heat, swelling, pain

28
Q

Stages of inflammation

A

inflammatory chemical release, vasodilation and increased vascular permeability, phagocyte mobilization

29
Q

inflammatory chemical release

A

chemicals are released into ECF by injured tissues or immune cells

30
Q

inflammatory chemical release example

A

histamine released by mast cells

31
Q

other inflammatory mediators besides histamine

A

kinins, prostaglandins (PGs), cytokines, complement (if pathogens are involved)

32
Q

What do inflammatory mediators do?

A

cause vasodilation of local arteries, make capillaries leaky, attract phagocytes to the area

33
Q

Vasodilation causes..

A

hyperemia - congestion with blood which leads to redness and heat

34
Q

increased capillary permeability causes

A

exudate - fluid containing clotting factors and antibodies to leak into tissue

35
Q

Benefits of edema

A

surge of fluid in tissue sweeps foreign material into lymphatic vessels for processing in lymph nodes; delivers clotting proteins and complement to area

36
Q

phagocyte mobilization

A

neutrophils flood area first, macrophages follow; if inflammation is due to pathogens, complement is activated, adaptive immunity elements arrive

37
Q

Steps for phagocyte mobilization:

A

(1) Leukocytosis, (2) Margination, (3) Deapedesis, (4) Chemotaxis

38
Q

Leukocytosis

A

release of neutrophils from bone marrow in response to leukocytosis-inducing factors from injured cells

39
Q

Margination

A

endothelial cells of capillaries in inflamed area project cell adhesion molecules (CAMs) into vessel lumen that grab onto passing neutrophils, causing them to slow and roll along, clinging to vessel wall

40
Q

Deapedesis

A

neutrophils flatten and squeeze between endothelial cells, moving into interstitial spaces

41
Q

Chemotaxis

A

inflammatory chemicals act as chemotactic agents that promote positive chemotaxis of neutrophils toward injured area

42
Q

___ hours after leaving the bloodstream, chemotactic agens are transformed into ____

A

12; macrophages

43
Q

Pus

A

creamy yellow mixture of dead neutrophils, tissue/cells, and living/dead pathogens

44
Q

Abscess

A

collagen fibers are laid down, walling off sac of pus; may need to be surgically drained

45
Q

granulomas

A

area of infected macrophages surrounded by uninfected macrophages and outer capsule

46
Q

antimicrobial proteins enhance innate defense by

A

attacking microorganisms directly or hindering their ability to reproduce

47
Q

Most important antimicrobial proteins

A

interferons, complement proteins

48
Q

interferons (IFN)

A

family of immune-modulating proteins

49
Q

complement system

A

consists of ~20 blood proteins that circulate in blood in inactive form

50
Q

complement

A

activation enhances inflammation and directly destroys bacteria; enhances both innate and adaptive defenses

51
Q

Complement system can be activated by three different pathways

A

classical, lectin, alternative

52
Q

Classical pathway

A

antibodies first bind to invading organisms and then bind to complement components, activating them; once ignition complement proteins are activated, an activation cascade is triggered

53
Q

Lectin pathway

A

lectins are produced by innate system to recognize foreign invaders; when it’s bound to specific sugars on foreign invaders, it can also bind and activate complement

54
Q

Alternative pathway

A

complement cascade is activated spontaneously when certain complement factors bind directly to foreign invader; lack of inhibitors on microorganism’s surface allows process to proceed

55
Q

Cell lysis begins when

A

C3b binds to target cell, triggering insertion of complement proteins called membrane attack complex (MAC) into cell’s membrane; MAC forms and stabilizes hole in membrane of microbe, causing influx of water and lysis of microbe

56
Q

pyrogens

A

act on body’s thermostat in hypothalamus, raising body temp

57
Q

Benefits of moderate fever

A

causes liver and spleen to sequester iron and zinc (needed by microorganisms); increases metabolic rate, which increases rate of repair

58
Q

Natural killer (NK) cells

A

promote apoptosis by directly attacking virus-infected or cancerous body cells; recognize general abnormalities rather than specific antigens

59
Q

inflammatory response

A

prevents injurious agents from spreading to adjacent tissues, disposes of pathogens and dead tissue cells, and promotes tissue repair; released inflammatory chemicals attract phagocytes to the area