Ch. 16 - Immune System Flashcards

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1
Q

Neutrophils

Where is production/function

A
  • Produced in bone marrow
  • Functions: phagocytosis, release chemicals involved in inflammation (vasodiltors, chemotaxins, etc.)
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2
Q

Basophils

Where is production/function

A
  • Produced in bone marrow
  • Functions: carry out functions in blood similar to those of mast cells in tissues
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3
Q

Eosinophils

Where is production/function

A
  • Produced in bone marrow
  • Function: destroy mulitcellular parasites, participate in immediate hypersensitivity reactions
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4
Q

Lymphocytes

A
  • Mature in bone marrow (B cells and NK cells) and thymus (T cells); activated in peripheral lymphoid organs
  • Function: serve as recognition cells in scpeficic immune responses and are essential for all aspects of these responses
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5
Q

B cells

A
  • Initiate anti-body mediated immune responses by binding specific antigens to the B cell’s plasma membrane receptors, which are immunoglobulins. - Upon activation, are transformed into plasma cells, which secrete antibodies.
  • Present antigen to helper T cells
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6
Q

Cytotoxic T cells

A

Bind to antigenes on plasma membrane of target cells (virus-infected cells, cancer cells, and tissue transplants) and directly destroy the cells

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7
Q

Helper T cells

A

Secrete cytokines that help to activate B cells, cytotoxic T cells, NK cells, and macrophages

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8
Q

Regulatory T cells

A

Act as inhibitors on other immune cells

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9
Q

NK cells

A
  • Bind directly and nonspecificially to virus-infected cells and cancer cells and kill them
  • function as killer cells in antibody-dependent cellular cytotoxicity (ADCC)
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10
Q

Plasma Cells

A
  • secrete peripheral lymphoid organs; differentiate from B cells during immune responses
  • secrete antibodies
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11
Q

Macrophages

A
  • produced in bone marrow; reside in almost all tissues and organs; differentiate from monocytes
  • functions:
    - phagocytosis,
    - extracellular killing via secretion of toxic chemicals
    - process and present antigens to helper T cells
    - Secrete cytokines involved in inflammation, activation and differentiation of helper T cells, and systemic repsonses to infection or injury (acute phase response)
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12
Q

Dendritic Cells

A

Produced: almost all tissues and organs; microglia in the CNS
Function: phagocytosis, antigen presentation

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13
Q

Mast Cells

A

Produced: bone marrow; reside in almost all tissues and organs; differentiate from bone marrow cells
Function: release histamine and other chemicals involved in inflammation

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14
Q

Innate Immunity

A

Nonspecific in that the identity of the target is not recognized

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15
Q

Adaptive Immunity

A

specific in that the target’s identity is recognized

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16
Q

Lymphatic Vessels begin as:

A

Fenestrated capillaries composed of a single layer of endothelium attached to a basement membrane

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17
Q

What is transported through Lymphatic vessels?

A

Lymph (similar to plasma) is transported through progressively bigger vessels, through lymph nodes, until it reaches vena cava

Larger lymphatic vessels contain one-way valves and smooth muscle

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18
Q

Primary lymphoid organs

A
  • bone marrow and thymus
  • initial sites of lymphocyte development
  • naive lymphocytes (have not been activated by a specific antigen)
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19
Q

Secondary lymphoid organs

A
  • lymph nodes, spleen, tonsils, and lymphocyte accumulations in the linings of the intestinal, respiratory, genital, and urinary tracts.
  • where the naive lymphocytes are activated to participate in adaptive immune responses
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20
Q

Thymus

A
  • Flat, bi-lobed organ located in superior mediastinum above heart
  • enlarges during childhood, then starts to atrophy as we enter our 20s
  • each lobe is comprised of lobules held together by areolar connective tissue
  • each lobe consists of a medullary region and cortical region
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21
Q

Bone marrow is the site of:

A

Leukopoiesis

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22
Q

Lymph nodes

A

follicles consisting of lymphatic and non-lymphatic cells surrounded by a network of lymphatic capillaries
- each is supplied by afferent lymphatic vessels and drained by efferent lymph. vessels

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23
Q

Outermost cortex of lymph nodes

A

B-lymphocytes, macrophages, dendritic cells

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24
Q

Paracortex of lymph nodes

A

T-lymphocytes, dendritic cells

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25
Q

Medulla of lymph nodes

A

B-lymphocytes, epithelial reticular cells

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26
Q

The spleen

A
  • filters blood, stores erythrocytes, removes defective erythrocytes/platelets, recycles iron (important for fighting infection)
  • lies between 9th and 11th rib on left side of body
  • contains red pulp and white pulp
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27
Q

Red Pulp in spleen

A

contains macrophages, erythrocytes, platelets, granulocytes, reticular cells, fibers

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28
Q

Cluster of Differentiation (CD)

A
  • numerical system for classifying proteins expressed on the surface of leukocytes
  • CD antigen is protein expressed on the surface of some but not all lymphocytes
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29
Q

Common characteristics of Lymphocytes

A

contain a single, large nucleus, a small amount cytoplasm, and a wide range of proteins expressed on their surface

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30
Q

B lymphocytes

A

develop in bone marrow

31
Q

T lymphocytes

A

begin development in bone marrow but complete it in thymus

32
Q

Cytotoxic T cells (TC)

A
  • designed to destroy virus-infected and tumor cells
  • play key role in transplant rejection
  • release perforin, granzymes, and granulysin
  • expresses CD8 on its surface for differentiation (forms dimer and interacts with MHC 1 molecule on infected cells)
33
Q

Memory T cells (TM)

A

carry the memory of antigen exposure after the antigen has left the body
- refers to clonal growth of a T-cell that recognizes a specific antigen

34
Q

Regulatory T cells (TR)

A
  • maintain immunological tolerance
  • block T cell-mediated immune responses at the end of the response window
  • also help to inhibit the activity of T-lymphocytes that recognizes self-antigens
35
Q

Helper T cells (TH)

A

assist other lymphocytes by aiding in the maturation of B-lymphocytes into plasma cells

36
Q

Natural Killer Cells

A
  • bridge between innate and adaptive immune system
37
Q

List all of the T-Lymphocytes

A
  1. T-memory
  2. T-helper
  3. T-regulatory
  4. T-cytotoxic
  5. NK cells
  6. Mucosal-associated invariant T-cells
  7. Gamma delta T-lymphocytes (in gut)
38
Q

Memory B Cells

A
  • carry the memory of previous exposure to antigen
  • generated after exposure to antigen by cytokine signaling
39
Q

Plasma B cells

A
  • long-lived, non-proliferating antibody-secreting cells
  • arise after exposure to antigen
40
Q

Other B cell types

A
  • plasmablasts
  • follicular B cells
  • Marginal zone B cells
  • Regulatory B cells
  • Naive B cells
41
Q

Positive Selection of lymphocytes

A

ensures lymphocytes are able to respond to antigen

42
Q

Negative selection of lymphocytes

A

removes lymphocytes that bind strongly to self antigens

43
Q

Outcomes of Negative Selection of Lymphocytes:

A
  • Receptor Editing: change the lymphocyte receptor so it no longer recognizes self antigens
  • Anergy: change the lymphocyte so it is no longer capable of an immune response
  • Apoptosis: clonal deletion and cell death
  • Ignorance: continue maturation
44
Q

Flow of innate immunity

A

Foreign threats -> physical barriers (skin, mucosal membranes, tears, saliva, stomach acid, sebum) -> chemicals, proteins, and cells (histamine, complement, neutrophils, eosinophils, basophils, NK cells, macrophages) -> stereotypic response (fever, inflammation)

45
Q

Opsonin

A

any substance or pathogen molecule that links a pathogen to an innate immune cell such as a phagocyte

46
Q

Complement

A

family of plasma proteins (including C3b) activated during inflammation by either the classical complement pathway (adaptive immunity) or alternate complement pathway (innate immunity); not only stimulates many of the steps of inflammation but mediates extracellular killing via the membrane attack complex.

47
Q

Interferons

A

chemical mediators produced by virus-infected cells that stimulate the production of intracellular proteins that inhibit viral replication

48
Q

Toll-like Receptors (TLRs)

A

evolutionary ancient proteins which recognize pathogen-associated molecular patterns (PAMPs) that are shared features of many pathogens
- present on membranes of dedritic cells, macrophages, and certain nonimmune cells
- binding of pathogen to a TLR generates intracellular signals that results in secretion of inflammatory mediators

49
Q

Features of the Skin

A
  • first line of defense against foreign threats
  • epidermis: waterproof, chemically resistant to bacterial enzymes
  • glands: maintain surface pH of 3-5, blocking the growth of most microorganisms
  • mucosal membranes contain anti-pathogenic substances (lysozymes)
50
Q

(T/F): Cytokines affect both the innate and adaptive immune systems

A

True

51
Q

Features of Cytokines

A
  • act in a autocrine, paracrine and endocrine manner
  • produced by a broad range of immune cells
  • overproduction of cytokines can lead to sickness and death
52
Q

Neutrophils

A
  • most abundant leukocyte
  • first responders to site of infection
  • release anti-microbial enzymes and “NETS” (neutrophil extracellular traps)
53
Q

Basophils

A
  • comprise ~1% of leukocytes
  • release histamines (more permeability) at site of infection
  • responsible for symptoms of allergies
54
Q

Mast Cells

A
  • release histamine (expand capillaries, more permeability), heparin (allows blood to flow faster), and other compounds
  • Also responsible for symptoms of allergies
55
Q

Eosinophils

A
  • comprise ~6% of leukocytes
  • release histamines
  • highly effective against parasites
56
Q

Features of NK Cells

A
  • able to induce apoptosis in virus-infected and cancer cells
  • release granules containing powerful proteases and perforin
  • also secrete alpha-defensins (anti-microbial peptides)
  • people w/ an impairment in NK cell development display a heightened incidence of blood cancer
57
Q

Process of Macrophage Phagocytosis:

A
  1. macrophages drawn to site by chemotaxis
  2. physical interaction between macrophage and foregin threat
  3. macrophages produce pseudopia that extend around foreign threat
  4. pseudopia fuse foreign threat within a vesicle forming a phagosome
  5. proteases and toxic chemicals in lysosome kill foregin threat
  6. parts of the foreign threat are exposed on the cell surface-antigen presentation
58
Q

Most complements are produced in the ________ in ____________ forms.

A

liver;inactive

59
Q

Most complements are produced in the ________ in ____________ forms.

A

liver;inactive

60
Q

____ separate pathways all converge to produce ____ and ____ convertase activities.

A

3 separate pathways all converge to produce C3 and C5 convertase activities.

61
Q

The ________________ opens pores on target cells.

A

membrane attack complex

62
Q

Inflammation is:

A

a stereotypic innate immune response

63
Q

Features of Antigens

A
  • antigen = anything that can trigger an adaptive immune response
  • immune system recognizes epitopes - discrete sites on macromolecules
  • any molecule has the ability to act as an antigen, but some are more potent than others
    • proteins are most potent, followed by sugars
  • common antigens: componenets of bacteria, viruses, pollen, animal dander, food, drugs

Adaptive Immunity

64
Q

Functions of antibodies in adaptive immunity:

A
  • antigen neutralization
  • antigen agglutination
  • antigen precipitation
  • complement activation
  • lymphocyte recruitment and activation
65
Q

Antigen Neutralization

A

covering and blocking the surface of the antigen

66
Q

Antigen Agglutination

A

clumping of antigens into larger complexes more readily recognized by macrophages

67
Q

Antigen Precipitation

A

bringing antigens out of solution, making them more easily recognized by macrophages

68
Q

Complement activation

A

through Fc region; leading to cell lysis and attraction of other leukocytes

69
Q

Primary vs. Secondary antibody responses

A
  • Primary phase starts with IgM, while secondary phase starts with IgG
  • difference in primary and secondary response is due to presence of memory B cells in secondary response
  • antibodies are more rapidly produced in secondary response
70
Q

Causes of Autoimmune diseases

A

unknown, but may include molecular mimicry, triggering of an immune response that bypasses TH cell movement, or a deficiency in TR cells

71
Q

Treatment of Autoimmune diseases

A

immunosuppressive drugs, removal of thymus, plasmapheresis

72
Q

Examples of Autoimmune Diseases

A
  • Celiac/IBS
  • Diabetes
  • Graves
  • Multiple Sclerosis
  • Psoriasis
  • Rheumatoid Arthritis
73
Q

Aging-related changes in the immune system

A
  • tissues and organs related to immunity decrease in size and become less repsonsive to the presence of pathogens
  • elderly are more likely to have to take immunosuppressive drugs for other conditions (e.g. chemotherapy for cancer)
  • inability to produce and mature new T lymphocytes due to replacement of thymus tissue with adipose tissue
  • fewer antibodies and memory B cells are produced, reduing vaccine effectiveness
  • accumulation of damage caused by autoimmune diseases that developed earlier