Immune System pt 1 Flashcards

1
Q

what are the functions of the immune system

A
  • recognize and eliminate pathogenic agents
  • disposing cells and debris (mutant cells to limit)
  • wound healing
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2
Q

describe the 3 components of the immune system

A
  • physical barriers
  • leukocytes
  • lymphoid tissues
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3
Q

briefly describe physical barriers

A
  • skin (cells packed together tightly)
  • mucous membranes (continuous barrier to skin)
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4
Q

describe the various layers of the skin and how they help with immunity

A
  • epidermis has tightly packed epithelial cells
  • dermis is thick connective tissue
  • provide good physical protection unless pierced
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5
Q

where can we find mucous membranes and what is their purpose

A
  • nose, mouth, anus, vagina make viscous mucous to block particles
  • GI tract and stomach make acids to kill microorganisms
  • next level of defense if skin not applicable
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6
Q

what are the types of leukocytes

A
  • neutrophils
  • eosinophil
  • basophil
  • monocyte
  • lymphocyte

these are WBCs

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7
Q

what are the categories of leukocytes

A
  • granulocytes (BENG)
  • agranulocytes (LAM)
  • based on presence of granules in cytoplasm
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8
Q

how do leukocytes derive

A

hemopoietic/hematopoietic stem cells in bone marrow

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9
Q

describe granulocytes

A
  • have cytoplasmic granules
  • contain secretory products
  • release thru degranulation
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10
Q

describe phagocytes

A
  • engulf foreign particles and microorganisms and remove them from blood or tissues
  • neutrophils, eosinophils, monocytes (eat MEN) -> blood
  • macrophages, dendritic cells (DM) -> tissues
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11
Q

what are the cells that mature in tissues

A

macrophages, mast cells, dendritic cells

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12
Q

describe macrophages

A

cells that derive from monocytes

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13
Q

describe mast cells; where are they found, what do they secrete

A
  • cells forming in bone marrow from hematopoietic stem cells
  • found in mucous membranes
  • secrete histamine
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14
Q

describe dendritic cells

A
  • cells forming in bone marrow from hematopoietic stem cells
  • activate certain T-cells
  • EX phagocytose pathogens
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15
Q

what are the roles of lymphocytes

A

to provide:
- diversity
- specificity
- memory
- ability to distinguish self from non-self in immune system

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16
Q

what are the main types of lymphocytes

A
  • B cells
  • T cells
  • null cells (most natural killer = NK)
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17
Q

describe B cells, what is their speed

A
  • flag antigens (targets) with antibodies
  • intermediate speed
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18
Q

draw the pathway of B cell interacting with antigen

A

B cell contacts antigen so it differentiates into a plasma cell which then secrete antibodies (immunoglobins) that attach onto foreign invader

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19
Q

describe T cells

A
  • direct attackers to foreign or abnormal cells (infected, mutant, transplanted)
  • slowest speed
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20
Q

draw pathway of T cell interacting with infected cells

A

T cell contacts infected cells and after days it turns into a cytotoxic T cell which secretes molecules that make pores in the target cell’s membrane which causes the cell to fill with fluid which causes cell to rupture

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21
Q

describe NK cells

A
  • small proportion of circulating lymphocytes
  • crucial for fighting viral infections
  • kill virus-infected cells which limits new virus production
  • use similar mechanism to T cells but recognize infected cells differently
  • fastest response
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22
Q

what are the 2 types of lymphoid tissues

A

central (primary) and peripheral (secondary)

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23
Q

describe central/primary tissues

A
  • lymphocytes made and mature here
  • bone marrow, thymus, fetal liver
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24
Q

describe cell development in bone marrow

A
  • leukocytes and RBCs
  • T cells migrate to thymus for maturation
  • B and T cells migrate to peripheral tissues after maturity
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25
Q

describe peripheral/secondary tissues

A
  • collections of B & T cells, macrophages
  • spleen, lymph nodes, tonsils, adenoids, appendix, lymph nodules in GI, Peyer’s patches in small intestine
26
Q

what pathogens activate immune response

A

virus, bacterium, fungi, parasites

27
Q

describe bacteria as a pathogen

A
  • gram + and - categories
  • can infect in different ways (stick and release toxins, endo- and exo- toxins)
28
Q

describe viruses as a pathogen

A
  • only takes small amt time to start extreme cascade
29
Q

describe parasites as a pathogen

A
  • go thru life cycles very quickly
  • typically spread by vectors (flies, mosquitos, food w/ eggs)
  • each generation will make a new protein to be one step ahead of your immune system which allows it to continue living
  • EX tapeworms, hookworms, trypanozoans
30
Q

describe fungi as a pathogen

A
  • immune system is responding to spores
  • mycoses diseases caused by them
31
Q

draw out the layers of defense

A

barriers -> non-specific immune response -> specific immune response -> pathogen destruction/suppression

32
Q

describe barriers as a layer of defense

A
  • physical and chemical (enzymes, antibodies, pH)
33
Q

describe non-specific immune response

A
  • rapid, non-specific, no memory
  • WBCs
  • chemicals (complement system, interferons)
34
Q

describe specific (adaptive) immune response

A
  • slow, specific, memory
  • cell-mediated responses (B; T cytotoxic, helper, regulatory)
  • antibody-mediated responses (antibodies)
35
Q

what are some types of nonspecific defenses

A
  • physical barriers
  • inflammation
  • interferons
  • complement system
36
Q

how do nonspecific defenses distinguish self from non-self

A
  • distinguish self from non-self via pathogen associate molecular patterns (PAMPs)
  • proteins associated w/ nonspecific defense act as pattern recognition receptors and bind PAMPs
37
Q

describe inflammation as a defense mechanism

A

series of events that cause accumulation of proteins, fluid, and phagocytes in an injured or invaded area

38
Q

draw the flow to steps of inflammation

A
  • macrophages engulf debris and foreign matter
  • capillaries dilate and become more permeable
  • foreign matter is contained
  • more leukocytes migrate to area
  • leukocytes clear infection
39
Q

describe the phagocytosis stage of inflammation

A
  • macrophages detect bacteria thru receptors
  • cytokine proteins important for cell signaling (autocrine, paracrine)
40
Q

describe the dilation of capillaries stage of inflammation

A
  • blood flow increases due to histamine dilating capillaries
  • the more histamine releases, the more dilation that happens to a point
  • fluid, leukocytes, defensive proteins release to tissues
41
Q

describe the containment stage of inflammation

A
  • mast cells and basophils release heparin
  • heparin prevents clot formations initially so that leukocytes can access the area first
  • the clot formed will have the pathogen
42
Q

describe the leukocyte migration/proliferation stage of inflammation

A
  • cytokines trigger movement of leukocytes
  • neutrophil migration takes 1 hr
  • monocyte migration to macrophages takes 10 hrs
  • leukocytosis
43
Q

what are the steps of movement that cytokine triggers for leukocytes

A
  • margination
  • attachment
  • diapedesis
  • chemotaxis
44
Q

describe the clearing of infection stage of inflammation

A
  • neutrophils and macrophages clear the tissue thru phagocytosis and secretion of cytokines
45
Q

describe chemotaxis

A
  • cytokines get into tissue and gain ability to recognize bacteria by secretion of chemicals (interleukin 8)
46
Q

what are the steps to phagocytosis

A
  • attachment
  • internalization
  • degradation
  • exocytosis
47
Q

describe the attachment stage of phagocytosis

A
  • the substance that should be engulfed is recognized either by shape or pattern recognition receptors
  • opsonins are on surface of engulfing cell (small molecules)
48
Q

describe the internalization stage of phagocytosis

A
  • takes ~0.01s
  • phagosome and lysosome combine to make a secondary lysosome
49
Q

describe the degradation stage of phagocytosis

A

the lysosome enzymes degrade the phagocytosed product

50
Q

describe the exocytosis stage of phagocytosis

A

some degradation products are eliminated

51
Q

describe interferons as a defense mechanism

A
  • prevention of virus spread in body
  • interferes with viral replication
  • proteins are secreted by leukocytes and virus infected cells make interferon α and interferon β
52
Q

describe interferon γ

A
  • secreted from active T cells and NK cells
  • inhibits viral replication
  • enhances phagocytosis by macrophages
  • boosts antibody production in B cells
  • helps activate NK cells and cytotoxic T cells
  • inhibits cell division (defense from cancer and cancerous cells)
53
Q

describe a complement system

A
  • 30 plasma proteins resulting in mechanisms to kill invading microorganisms esp bacteria
  • can act (non)specifically depending on whether antibodies are present
  • can be activated using 3 pathways
54
Q

what are the pathways that can activate the complement system

A

classical, lectin, alternative

55
Q

what are the results of complement activation

A

opsonization, leukocyte recruitment, histamine secretion, MAC

56
Q

describe the classical pathway

A
  • depends on presence of antibodies (involving proteins C1-C9)
  • slow
  • antigen and antibody make c1 complex -> c2b and c4b fragments make c3 convertase -> c3 then hydrolyzes (leading into alternative)
57
Q

describe the alternative pathway

A
  • nonspecific
  • intermediate speed
  • doesn’t rely on production of antibodies
  • activates at point further along than classical (C3)
  • c3 hydrolyses into fragments -> C5 cleaved by c3b fragment -> c5b to c9 make cylindrical complex that bursts cell
58
Q

describe the lectin pathway

A
  • nonspecific
  • fastest
  • doesn’t rely on production of antibodies
  • lectins bind specific carbs
  • MBL + mannose -> MASP -> C2 and C4 proteins
59
Q

describe MAC

A
  • membrane attack complex
  • nonspecific
  • first complement protein attaches to bacterial cell -> cascade of protein activation slope on membrane -> MAC forms on pore
  • swelling of cell leads to lysis
60
Q

describe natural killer cells

A
  • early operation in nonspecific defense
  • recognize abnormal/infected cells
  • lysis of pathogen occurs thru secretion of perforins
  • can attack virus-infected cells w/out identifying virus
  • defense against viral infections, tumors, bacteria, and protozoans
  • part of specific immune response