Lymphatics + immunity Flashcards

1
Q

lymphatic system role

A

protect against disease

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1
Q

3 things lymphocytes respond to

A

environmental pathogens
toxins
abnormal body cells eg. cancer cells

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2
Q

structure of lymphatic vessels

A
  • endothelial cells loosely bound together w/ overlap
    -> acts as one way valve for entry of interstitial fluid
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3
Q

where does lymph from the right upper limb + right side of head + neck enter

A

right lymphatic duct -> into right subclavian vein

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4
Q

where does lymph from the rest of the body enter

A

thoracic duct -> empties into left subclavian vein

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5
Q

what is lymphedema

A
  • blockage of lymph drainage
  • interstitial fluid + causes severe swelling
  • fluid becomes stagnant + causes accumulation of toxins + pathogens
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6
Q

where are lymphocytes produced

A

lymphoid tissues
lymphoid organs
red bone marrow
-> travel to site of infection as part of immune response

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7
Q

where are T and B cells produced

A

T = thymus
B = bone marrow

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8
Q

function of cytotoxic T cells

A

attack virally infected cells
specific cell mediated immunity

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9
Q

function of memory T cells

A

formed in response to foreign substances
remain in body to give ‘immunity’

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10
Q

function of T helper cells

A

stimulate function of T and B cells

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11
Q

function of suppressor T cells

A

inhibit function of T + B cells

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12
Q

function of B cells + effects

A
  • differentiate into plasma cells
  • plasma cells produce + secrete antibodies
    -> binding of a specific antibody to a specific target antigen initiates specific antibody mediated immunity
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13
Q

NK cells function

A
  • responsible for immunological surveillance
  • attack foreign cells, virus infected cells + cancer cells
  • non-specific immunity
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14
Q

Distinguish b/t lymphoid tissues + lymphoid nodules

A

lymphoid tissues = connective tissue dominated by lymphocytes

lymphoid nodules = small, localised collection of lymphoid tissue
-> eg. respiratory tract (tonsils)

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15
Q

function of the thymus

A
  • produce hormones that develop + maintain normal immune system function

-> thymosin = protein produced in thymus that promotes production of lymphocytes

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16
Q

3 functions of the spleen

A
  • removal of abnormal blood cells + other blood components by phagocytosis
  • storage of iron recycled from RBCs
  • initiation of immune responses by B + T cells in response to antigens in circulating blood
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17
Q

list the 7 categories of innate immunity

A
  • physical barriers
  • phagocytes
  • immunological surveillance
  • interferons
  • complement
  • inflammatory response
  • fever
18
Q

2 examples of physical barriers

A

integumentary system
epithelia lining

19
Q

2 examples of microphages and how they work

A
  • neutrophils + eosinophils
    -> leave the bloodstream + enter peripheral tissues to fight infections
20
Q

how do activated macrophages respond to pathogens

A
  • engulf pathogens + destroy it with lysosomal enzymes
  • bind to pathogen so other cells can destroy it
  • destroy pathogen by releasing toxic chemicals into interstitial fluid
21
Q

difference b/t fixed + free macrophages

A

fixed = stay in specific tissues or organs eg. dermis + bone marrow
free = travel throughout whole body

22
Q

how do NK cells perform immunological surveillance

A

recognise + destroy abnormal cells by:
- identifying + attaching to abnormal cell eg. cancer cell or virally infected cell
- golgi apparatus in NK cell forming perforin vesicles
- vesicles release proteins called perforins
- perforins lyse abnormal plasma membrane

23
Q

steps to interferon defence

A
  • cytokines released b y activated lymphocytes + macrophages
  • infection of a cell by a virus stimulates expression of interferon proteins
  • interferon proteins are exocytosed + bind to receptors on an uninfected cell -> triggers production of antiviral proteins
  • antiviral proteins block replication of the virus -> causes death
24
Q

how does complement defence work

A
  • plasma contains 11 complement proteins which induce lysis of foreign cells
  • enhances both non-specific + specific defences
  • complements antibody action
25
Q

names of 3 complement pathways + overview

A
  • classical pathway = most rapid + effective -> C1 attached to antibodies (already attached to cell wall) + causes cascade -> C3b binds to wall + enhances phagocytosis
  • lectin pathway = activated by protein mannose-binding lectin -> binds to carbohydrates on cells surface
  • alternative pathway = complement proteins interact in plasma -> C3 splits into C3a + C3b / C3a activates inflammatory response
26
Q

3 roles of complement proteins

A
  • forming membrane attack complexes (MAC) to destroy target plasma membranes
  • increased phagocytosis by opsonisation
  • inflammation
27
Q

4 key signs of inflammation

A
  • swelling + pain (b/c increased tissue fluid)
  • redness + heat (b/c increased blood flow)
28
Q

how does fever work to disrupt pathogen lifecycle

A
  • increased body temp (>37 degrees) caused by release of pyrogens (associated w/ pathogens + toxins)
  • signals to hypothalamus to disrupt lifecycle of pathogen
29
Q

list the 4 properties of immunity

A
  • specificity
  • versatility
  • memory
  • tolerance
30
Q

define specifity

A

each T or B cell only responds to 1 antigen

31
Q

define versatility

A

body produces many types of lymphocytes
-> each fights dif. type of antigen

32
Q

define memory

A

some active lymphocytes remain in circulation + provide immunity against new exposure

33
Q

define tolerance

A

immune system ignores self antigens

34
Q

differentiate b/t MHC I + II proteins

A
  • MHC I = found in membranes of all nucleated cells -> non self antigen displayed on infected cell
  • MHC II = only found on antigen presenting cells

both activate T cells

35
Q

list 3 types of antigen presenting cells

A

macrophages (liver + CNS) - phagocytic

lagerhans cells (in skin) + dendritic cells (in lymph nodes + spleen) - non-phagocytic

36
Q

steps to MHC I antigen presentation

A
  • antigen presentation triggered by viral/bacterial infection of body cell
  • infection causes appearance of abnormal peptides in cytoplasm
  • abnormal peptides incorporated into MHC I proteins by ER
  • MHC proteins reach plasma membrane via PPP
  • abnormal peptides displayed by MHC I on Pm
37
Q

steps to MHC II antigen presentation

A
  • phagocytic APCs engulf extracellular pathogen
  • antigenic fragments produced by lysosomes
  • MHC II proteins produced by ER
  • antigenic fragments bound to MHC II proteins + displayed on PM
38
Q

what are cluster differentiation markers (CD)

A

molecular mechanism of antigen recognition

39
Q

function of CD8 + CD4 markers

A

CD8 = found on cytotoxic T cells + suppressor T cells + respond to antigens on MHC I proteins

CD4 = found on helper T cells + respond to antigens on MHC II cells

40
Q

steps to T cell mediated immunity

A
  1. antigen recognition = when CD8 cell encounters MHC I protein antigen
  2. costimulation = costimulation activates CD8 cell
  3. activation + cell division = T cells activated + divide into active Tc cells + T memory cells
  4. destruction of target cells = Tc cell releases perforins + cytokines
41
Q

steps to antibody mediated immunity

A
  1. sensitisation = antigens bind to antibodies on inactive B cell -> sensitised
  2. activation = T helper cell releases cytokines in respond to non-self MHC II antigen -> activation
  3. division + differentiation = B cells divide into plasma cells (produce antibodies) + B memory cells
42
Q

describe the 5 types of antibodies + their roles

A

IgG = majority of defence
IgM = secreted first after primary exposure to antigen
IgA = attacks pathogens before entering body tissues
IgE = accelerates inflammation upon antigen exposure
IgD = binds antigens in extracellular fluid to B cells