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han 202 > Chapter 21 Immune System > Flashcards

Chapter 21 Immune System Flashcards

1
Q

Which of the following contributes to the flow of lymph through lymphatic vessels

A

The pumping of the heart
The milking action of skeletal muscle contraction*
Pressure changes in the thorax that result from breathing*
Both b and c****
All of the above

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2
Q

The thymus is important for ____

A
  • T lymphocyte maturation*
  • removal of foreign antigens
  • B lymphocyte maturation
  • secretion of hormones that promote B lymphocyte immunocompetence
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3
Q

Areas of the spleen that contain large aggregation of lymphocytes are known as

A
  • peyers patches
  • adenoids
  • white pulp*
  • red pulp
  • lymph nodes
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4
Q

Immunity

A
  • bodys defense against invaders
  • resistance to disease
  • immune system has two intrinsic systems:
  • innate
  • adaptive
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5
Q

innate immunity

A
  • nonspecific defense system
  • born with
  • 1st line of defense- surface barriers- skin, mucous membranes
  • 2nd line of defense- internal defenses
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6
Q

adaptive immunity

A
  • specific defense system
  • active
  • 3rd line of defense:
  • humoral immunity
  • cellular immunity
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7
Q

Internal defenses

A
  • 2nd line of innate defense
  • cells and chemicals
  • necessary if microorganisms invade deeper tissues
    1. phagocytes
    1. Natural Killer (NK) cells
    1. inflammation- inflammatory response (macrophages, mast cells, WBCs, and inflammatory chemicals)
    1. antimicrobial proteins (interferons and complement proteins)
    1. fever
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8
Q

Surface barriers

A
  • 1st line of innate defense
  • skin (keratin)- physical barrier to most microorganisms
  • mucosae provide similar mechanical barriers
  • mucous membranes
  • hair
  • protective chemicals inhibit or destroy microorganisms
  • skin acidity
  • lipids in sebum and dermcidin in sweat- toxic
  • stomach acids
  • lysozyme of saliva and lacrimal fluid
  • mucus- traps microorgansisms
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9
Q

humoral and cellular immunity

A
  • 3rd line of defense
  • humoral immunity- B cells
  • cellular immunity- T cells
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10
Q

phagocytes: neutrophils and macrophages (and eosinophil)

A
  • neutrophils- most common
  • macrophages- develop from monocytes to become the chief phagocytic cells
  • phagocyte mobilization:
  • leukocytosis
  • margination
  • diapedesis
  • chemotaxis
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11
Q

phagocyte mobilization

A
    1. leukocytosis- neutrophils enter blood from bone marrow
    1. margination- neutrophils cling to capillary wall
    1. diapedesis- neutrophils flatten and squeeze out of capillaries
    1. chemotaxis- neutrophils follow chemical trail
  • innate defense -> internal defense
  • inflammatory chemicals diffusing from the inflamed site act as chemotactic agents
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12
Q

Phagocytosis: Step 1: Adherence of phagocyte to pathogen

A
  • facilitated by OPSONIZATION (to make tasty)- coating of pathogen by complement proteins or antibodies -> attracts the phagocyte
  • destruction of pathogens:
  • acidification and digestion by lysosomal enzymes
  • respiratory burst- release of cell killing free radicals
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13
Q

Natural Killer (NK) cells

A
  • large granular lymphocytes
  • target cells that lack self cell-surface receptors, look for ABNORMAL cells
  • induce apoptosis (suicide) in cancer cells and virus- infected cells before immune system is activated
  • secrete potent chemicals that enhance the inflammatory response (positive feedback)
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14
Q

Inflammatory Response

A
  • triggered whenever body tissues are injured or infected
  • prevents the spread of damaged agents
  • cardinal signs of acute inflammation:
    1. redness
    1. heat
    1. swelling
    1. pain
  • (sometimes) 5. impairment of function
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15
Q

Benefits of inflammation

A
  • dilutes harmful substances
  • brings in useful substances
  • disposes of debris
  • pain immobilizes
  • prevent spread of damaging agents
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16
Q

steps of inflammatory response

A
  • tissue injury
  • release of different factors and chemicals -> initiate inflammatory response (histamine, complement proteins, prostaglandins)
  • vasodilation of arteries -> local hyperemia -> heat -> redness -> increased metabolic rate of cells -> increased healing
  • increased capillary permeability -> leak fluid -> pain -> swelling -> possible temporary limitation of joint movement -> increased healing
  • neutrophils, monocytes etc. released
  • leukocytosis factors
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17
Q

antimicrobial proteins

A
  • interferons (IFNs) and complement proteins
  • attack microorganisms directly
  • hinder microorganisms ability to reproduce
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18
Q

interferons

A
  • interfere with viral replication
  • viral infected cells are activated to secrete IFNs
  • IFNs enter neighboring cells
  • neighboring cells produce antiviral proteins that block viral reproduction
  • activate macrophages and mobilize NK cells
    1. virus enters cell
    1. interferon genes switch on
    1. cells produces interferon molecules
    1. interferon binding stimulates cell to turn on genes for antiviral proteins
    1. antiviral proteins block viral reproduction
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19
Q

complement activation

A
  • activated complement
    1. enhances inflammation
    1. promotes phagocytosis (opsonization)
    1. causes cell lysis
  • formation of a membrane attack complex (MAC)
  • MAC causes cell lysis by inducing a massive influx of water by making a hole
  • complement enhances the effectiveness of both the innate and adaptive defenses
  • complement system is major mechanisms for destroying foreign substances
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20
Q

fever

A
  • systemic response to invading microorganisms
  • leukocytes and macrophages secrete pyrogens
  • pyrogens reset the body’s thermostat upward (hypothalamus)
  • high fevers are dangerous because heat denatures enzymes
  • benefits of moderate fever -> increases metabolic rate, which speeds up repair
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21
Q

inflammation ________

A
  • is caused by bacterial activity to enhance the spread of disease
  • is caused by viral activity to enhance the spread of the disease
  • slows the healing process with swelling that can impair bodily function
  • brings more leukocytes to the sight of infection***
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22
Q

interferons __________

A
  • are virus-specific, so that an interferon produced against one virus could not protect cells against another virus
  • act by increasing the rate of cell division
  • interfere with viral replication within cells*
  • are routinely used in nasal sprays for the common cold
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23
Q

adaptive defenses

A
  • the adaptive immune (specific defense) system - immunity to one disease doesn’t protect you against a different disease
  • protects against infectious agents and abnormal body cells
  • amplifies the inflammatory response
  • activated complement
  • specific
  • systemic
  • has memory
  • HUMORAL
  • CELLULAR
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24
Q

adaptive immune system: Humoral

A
  • antibody mediated

- immunity (“humors” are fluids) - B cells!

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25
Q

Adaptive immune response- Cellular

A
  • cell-mediated immunity

- T cells

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26
Q

antigens- Antibody Generator

A
  • antigens are the targets of immune response

- most are large, complex molecules not normally found in the body (nonself)

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27
Q

complete antigens

A
  • large molecules
  • immunogenicity- can stimulate specific lymphocytes to multiply
  • reactivity- ability to react with these lymphocytes and antibodies
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28
Q

incomplete antigens- Haptens

A
  • small molecules
  • are not immunogenic
  • combine with body’s own proteins and cause an attack that is harmful not protective (animal dander, detergents)
  • dont react with our immune system -> combine with our own proteins
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29
Q

Antigenic Determinants

A
  • certain parts of an entire antigen that are immunogenic
  • antibodies and lymphocyte receptors bind to them
  • large, chemically simple molecules (e.g. plastics) have little or no immunogenicity
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30
Q

Self-Antigens: MHC proteins

A
  • protein molecules (self-antigens) on the surface of all your cells
  • these are the tags that label your cells as part of your cells -> NK cells attack if lacking!
  • self antigens are not foreign to you
  • antigenic to others in transfusions or grafts
  • MHC (major histocompatibility complex) proteins
  • presence of this protein allows immune system to differentiate btw our cells and foreigners
  • MHC are cells’ identity markers
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31
Q

cells of the adaptive immune system: lymphocytes

A
  • two types of lymphocytes: B and T lymphocytes
  • B cells- humoral immunity
  • T cells- cell-mediated immunity
  • react to only one type of antigenic determinant
  • training process is very selective -> only 2% survive

-antigen-presenting cells (APCs)

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32
Q

antigen-presenting cells (APCs)

A
  • do not respond to specific antigens
  • play essential auxiliary roles in immunity
  • dendritic cells
  • macrophages
  • B lymphocytes
  • engulf antigens
  • present fragments of antigens to be recognized by T cells -> like signal flags on their surface
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33
Q

B cells

A
  • form in bone marrow
  • mature in RED bone marrow
  • seed the secondary lymphoid organs and circulate through blood and lymph
  • antigen receptors bind to antigen -> activation
  • multiplies and differentiates
  • memory cells or effector cells form
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34
Q

T cells

A
  • bone in bone marrow
  • mature in thymus
  • seed the secondary lymphoid organs and circulate through blood and lymph
  • antigen receptors bind to antigen -> activation
  • multiplies and differentiates
  • memory cells or effector cells form
35
Q

Dendritic cells

A
  • APCs
  • capture antigens and enters lymph system to node
  • most important APC
36
Q

macrophages

A
  • APCs

- present antigens to t cells which activates them into voracious phagocytes

37
Q

B cells: APC

A
  • APCs

- presents antigens to T cell which assists in own activation

38
Q

adaptive immunity

A
  • uses lymphocytes, APCs, and specific molecules to identify and destroy Non self substances
  • depends upon the ability of its cells to recognize antigens by binding to them
  • communication with one another so that the whole system mounts a specific response
39
Q

Humoral immunity response

A
  • antigen challenge:
  • first encounter between an antigen and a naive immunocompetent lymphocyte
  • usually occurs in the spleen or a lymph node
  • if the lymphocyte is a B cell -> the antigen provokes a humoral immune response
  • antibodies are produced
40
Q

clonal selection

A
    1. B cell is activated when antigen bind to its surface receptor
    1. stimulated B cell grows to form a clone of identical cells bearing the same antigen-specific receptors
41
Q

fate of the clones

A
  • most clone cells become plasma cells
  • secrete specific antibodies at the rate of 2000 molecules per second for 4-5 days
  • activated B cells after meeting an antigen -> becomes a memory cell OR becomes a plasma cell (effector) cell -> becomes an antibody
42
Q

secreted antibodies

A
  • circulate in blood or lymph
  • bind to free antigens
  • mark the antigens for destruction
  • antibodies DO NOT kill antigens -> they just mark
43
Q

clones that do not become plasma cells become memory cells

A
  • provide immunological memory

- mount an immediate response to future exposures of the same antigen

44
Q

immunological memory: primary immune response

A
  • primary immune response
  • occurs on the first exposure to a specific antigen
  • lag period- 3-6 days
  • peak levels of plasma antibody are reached in 10 days
  • antibody levels then decline
  • occurs after a delay
45
Q

immunological memory: secondary immune response

A
  • occurs on re-exposure to the same antigen
  • sensitized memory cells respond within hours
  • antibody levels peak in 2-3 days at much higher levels
  • antibodies bind with greater affinity
  • antibody level can remain high for weeks to months
  • more efficient, powerful, longer response
46
Q

an advantage of innate immunity is _____

A
  • its barriers that prevent pathogens from entering into the body**
  • the specificity of its individual cells which specialize in the removal on one type of antigen
  • the numerous steps in the activation of its cells that can prevent autoimmune disease
  • the use of antibodies to cause cell lysis and kill invading cells
47
Q

a sample of jons blood shows a high level of pyrogens. This would indicate that jon

A
  • is feeling achy
  • is producing T lymphocytes
  • has a sore throat
  • is running a fever*** pyrogens increase baseline temperature -> fever
  • has a swollen lymph nodes
48
Q

active humoral immunity

A
  • occurs when B cells encounter antigens and produce specific antibodies against them
  • two types:
  • naturally acquired- response to a bacterial or viral infection- direct contact
  • artificially acquired- response to a vaccine of dead or attenuated pathogens
49
Q

vaccines

A
  • spare us the symptoms of the primary response
  • provide antigenic determinants that are immunogenic and reactive
  • vaccines have wiped out smallpox and have significantly reduced measles, polio, and whooping cough
  • edward jenner-
  • cowpox and milkmaids
  • vacca- cow
50
Q

passive humoral immunity

A
  • B cells are not challenged by antigens
  • antibodies “borrowed” from another source and lasts for a short period
  • drawbacks:
  • short lived
  • does not trigger memory
  • antibodies eventually are degraded
51
Q

passively naturally acquired humoral immunity

A

-antibodies delivered to a fetus via the placenta or to an infant through breast milk

52
Q

passively artificially acquired humoral immunity

A
  • infection of serum, such as gamma globulin (IVIG treatments)
  • protection is immediate but ends when antibodies naturally degrade in the body
  • example- antivenom for treatment of poisonous snake bites
53
Q

antibodies

A
  • immunoglobulins- gamma globulin portion of blood (Ig)
  • proteins secreted by plasma cells (from B cells)
  • capable of binding specifically with antigen detected by B cells
  • all antibodies can be grouped into 1 of 5 classes:
  • IgM
  • IgA
  • IgD
  • IgG
  • IgE
  • MADGE
54
Q

basic antibody structure

A
  • two identical heavy (H) chains (long) and two identical light chains (short)
  • variable (V) regions of each arm combine to form two identical antigen binding sites
  • constant (C) region determines antibody class -> (IgM, IgA, IgD, IgG, IgE)
55
Q

IgM

A
  • a pentamer (large)
  • first antibody released
  • potent agglutinating agent in blood plasma
  • readily fixes and activates complement
56
Q

IgA

A
  • secretory
  • monomer or dimer
  • in mucus and other secretions
  • found in body secretions -> saliva, sweat, milk
57
Q

IgD

A

-functions as a B cell receptor

58
Q

IgG

A
  • from a secondary and late primary responses
  • crosses the placental barrier
  • most abundant
59
Q

IgE

A
  • monomer active in some allergies and parasitic infections
  • causes mast cells and basophils to release histamine
  • inflammation
60
Q

Antibody targets

A
  • antibodies inactivate and tag antigens (antibodies cannot destroy antigens)
  • form antigen-antibody (immune) complexes
  • defensive mechanisms used by antibodies
    1. neutralization
    1. agglutination
    1. precipitation
    1. lysis- complement fixation
  • PLAN
61
Q

neutralization

A
  • surrounds
  • antibodies block specific sites on viruses or bacterial exotoxins
  • prevent these antigens from binding to receptors on tissue cells
  • antigen-antibody complexes undergo phagocytosis
62
Q

agglutination

A
  • clumps
  • cross linked antigen-antibody complexes agglutinate
  • ex. clumping of mismatched blood cells
  • these clumps are easily destroyed by phagocytes
63
Q

precipitation

A
  • soluble small molecules are cross-linked and fall out of solution
  • complexes precipitate and are subject to phagocytosis
64
Q

lysis: complement fixation and activation

A
  • main antibody defense against cellular antigens
  • their complement-binding sites trigger complement fixation into the cell’s surface
  • complement triggers cell lysis
65
Q

which of the following best describes an antibody’s mode of action

A
  • antibodies punch holes in bacterial cell membranes
  • antibodies immobilize antigens and mark them for destruction*
  • antibodies bind to antigens and transport them to the liver for excretion
  • antibodies secrete antiviral proteins
  • choice a and b are correct
66
Q

in passive immunity, the

A
  • immunity system attacks normal body cells
  • body is deliberately exposed to an antigen
  • body receive antibodies produced by other humans*
  • the body is given a dead form of the antigen
67
Q

cell-mediated immune response

A
  • t cells provide defense against INTRACELLULAR antigens
  • T cells:
  • cause inflammation
  • activate macrophages
  • get other T cells fired up
  • regulate much of immune system
68
Q

types of t cells

A
  • helper T cells- TH
  • cytotoxic T cells- TC -> destroy cells harboring foreign antigens
  • regulatory T cells- TREG
  • memory T cells
69
Q

comparison of humoral (B cell) and Cell-mediated response

A
  • antibodies of the humoral response are the simplest ammunition of the immune response
  • humoral response targets bacteria and molecules in EXTRACELLULAR environments (body secretions, tissue fluid, blood, and lymph- “humors”)
  • T cells of the cell-mediated recognize and response only to processed FRAGMENTS of antigens displayed on the surface of body cells
  • cell-mediated response targets body cells infected by viruses or bacteria, abnormal or cancerous cells, and cells of infused or transplanted foreign tissue
70
Q

antigen recognition

A
  • immunocompetent T cells are activated when their surface receptors bind to a recognized antigen (nonself)
  • t cells must simultaneously recognize:
  • nonself (the antigen)
  • self (an MHC protein of a body cell)
  • T cells cannot see free antigens, can only recognize fragments of antigens displayed on surface of cell ( b cell can recognize in bloodstream)
71
Q

T cell activation

A
  • primary T cell response peaks within a week
  • T cell apoptosis occurs between days 7 and 30
  • effector activity wanes as the amount of antigen declines
  • benefit of apoptosis- activated T cells are a hazard
  • memory T cells remain and mediate secondary responses
72
Q

activated T cells become either effector or memory T cells

A

-effector T cells -> helper, cytotoxic, regulatory

73
Q

helper T (Th) cells

A
  • play a central role in the adaptive immune response
  • once primed by APC presentation of antigen, they:
  • help activate T cells- activated CD8 into cytotoxic T cells
  • help activate B cells- B cells are useless until the helper T cell activates
  • induce T and B cell proliferation
  • activate macrophages and recruit other immune cells
  • WITHOUT HELPER T CELLS THERE IS NO IMMUNE RESPONSE
74
Q

roles of cytotoxic T (Tc) cells

A
  • only T cells that can directly attack and kill other cells
  • activated cytotoxic T cells circulate in blood and lymph and lymphoid organs in search of body cells displaying antigens they recognize
  • targets:
  • virus infected cells
  • cells with intracellular bacteria or parasites
  • cancer cell
  • foreign cells (transfusions or transplants)
    1. identifies foreign antigens on MHC 1 proteins and binds
    1. perforin and granzymes are released
    1. perforin molecules insert into target cell membrane -> forms a hole
    1. granzymes enter and activate enzymes that trigger apoptosis
    1. cytotoxic cells detach and search for another prey
75
Q

how is cytotoxic T cell mechanism of action similar to that of complement

A
  • cytotoxic T cells activate B cells to produce antibodies
  • cytotoxic T cells induce cell lysis with perforin a protein similar to complements MAC
  • cytotoxic T cells secrete the proteins that activate complement
  • cytotoxic T cells are antigen presenting cells similar to the complement proteins found of B cells
76
Q

Regulatory T (Treg) cells

A
  • dampen the immune response by direct contact or by inhibitory cytokines
  • important in preventing autoimmune reactions
  • also called suppressor T cells
77
Q

antibodies typically act extracellular in body fluids and are therefore considered part of the humoral branch of adaptive immunity proteins

A
  • true***- extracellular- humoral

- false

78
Q

disorders of immune system

A
  • immunodeficiencies
  • congenital and acquired conditions that cause immune cells, phagocytes, or complement to behave abnormally
  • SCID, lymphoma, HIV/AIDS
  • autoimmune diseases
  • hypersensitivity - immediate, subacute, delayed
79
Q

SCID- severe combine immunodeficiency syndrome

A
  • congenital immunodeficiency

- deficit of B and T cells

80
Q

immunodeficiencies: hodgkins disease

A
  • -an acquired immunodeficiency
  • cancer of the b cells
  • leads to immunodeficiency by depressing lymph code cells
81
Q

acquired immune deficiency syndrome (AIDS)

A

-cripple the immune system by interfering with the activity of helper T cells

82
Q

autoimmune diseases

A
  • immune system loses the ability to distinguish self from foreign
  • production of autoantibodies and sensitized TC cells that destroy body tissues
  • ex. multiple sclerosis, myasthenia gravis, type 1 diabetes mellitus, systemic lupus erythematous, glomerulonephritis, rheumatoid arthritis
83
Q

hypersensitivity

A
  • immune responses to a perceived (otherwise harmless) threat
  • causes tissue damage
  • different types are distinguished by their time course and whether antibodies or T cells are involved
  • antibodies cause immediate and subacute hypersensitivities
  • T cells cause delayed hypersensitivity
84
Q

types of hypersensitivities

A
  • immediate- local or systemic (IgE) - allergies, begins in seconds after contact
  • subacute- slow onset (IgM, IgG)- mismatched blood
  • delayed- onset 1-3 days- cytotoxic T cells -> ex. poison ivy

han 202 (16 decks)

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