chap 6- responding to antigens Flashcards

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1
Q

what are microbes

A

small cellular organisms that can only be seen with a microscope

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2
Q

what is an example of a protist

A

bacteria

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3
Q

example of protozoans

A

malaria

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4
Q

example of fungi

A

yeast or athletes foot

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5
Q

example of a virus

A

covid-19

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6
Q

example of prions

A

mad cow disease

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7
Q

how can pathogens be transmitted

A

person-person contact
airborne droplets
contact with contaminated objects, food or blood
injection of contaminated food or water
vectors that carry pathogenic agents and spread them to people

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8
Q

what is the pathway for disease to occur

A

1- gain entry to the organism
2- reach target cells
3- overcome body’s defense systems
4- become established at one or more sites
5- multiply rapidly
6- cause harm to the host and produce the symptoms of disease

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9
Q

what does the first line of defence do

A

stops pathogens from causing damage

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10
Q

is the first line of defense innate and non specific

A

yes

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11
Q

what does innate mean

A

from birth

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12
Q

what does non-specific mean

A

works on any pathogen

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13
Q

what do physical barriers do

A

act to stop pathogenic material from gaining entry into the body

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14
Q

example of physical barriers in animals

A

intact skin, mucus- membranes, sneezing/coughing/vomiting

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15
Q

example of physical barriers in plants

A

thick bark, wax coatings, cellulose cell wall

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16
Q

what do chemical barriers in animals do

A

chemicals attack pathogenic material

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17
Q

examples of chemical barriers in animals

A

stomach acid (contains HCl)
sweat/tears/saliva (contains lysozyme
fluid in lungs (contains surfactants)

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18
Q

examples of chemical barriers in plants

A

caffeine (is toxic to insects and fungi)
tannins (toxic to insects)
citronella (repels insects)

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19
Q

what do microbiota barriers do

A

act to prevent colonization of microorganisms that may be pathogenic.

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20
Q

when do be acquire normal microbiota

A

from birth

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21
Q

is the second line of defense innate and non-specific

A

yes

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22
Q

when does the second line of defence kick in

A

after microbes pass 1st line of defence

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23
Q

where does second line of defense mainly occur

A

at sight of infection

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24
Q

what does second line of defence react against

A

microbes

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25
Q

what is inflammation

A

the accumulation of fluid, plasma proteins and leukocytes that occurs when tissue is damaged/infected

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26
Q

what is inflammation characterized by

A

pain, redness, heat and swelling

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27
Q

what triggers the inflammatory response

A

the interaction between leukocytes and pathogens triggers the inflammatory response that results from the production, activation or release of substances such as complement proteins and cytokines.

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28
Q

what are leukocytes

A

all cells in the immune system are WBC (leukocytes). derived from pluripotent stem cells in bone marrow

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29
Q

what are phagocytes

A

WBC that engulfs foreign matter (endocytosis). they arrive at sight of infection first

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30
Q

what are the phagocytes

A

macrophages, neutrophils and dendritic cells

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31
Q

what are granulocytes

A

leukocytes with granules that have enzymes that are released during infections, allergic reactions and asthma

32
Q

can leukocytes be phagocytes and granulocytes

A

yes

33
Q

what are the granulocytes

A

neutrophils, eosinophils, mast cells and basophils.

34
Q

what is an antigen

A

any substance that triggers an immune response in the body

35
Q

what are antigen presenting cells

A

phagocytes that digest foreign material containing an antigen and display a fragment of this antigen on the surface of their membrane where it can be recognized by the adaptive immune response

36
Q

what are cytokines

A

small protein signalling molecules released by body cells in response to cell damage or presence of a pathogen. they trigger innate responses associated with the 2nd line of defense such as inducing inflammation and fever along with activating macrophages.

37
Q

what are macrophages

A

large phagocytes that tend to be located close to pathogen entry points. they engulf microbes, digest them and display a fragment on their surface. also release cytokines to initiate inflammatory response

38
Q

what are neutrophils

A

exist in bloodstream. engulf microbes and kill them with toxic chemicals. contain granules with antimicrobial compounds. also release cytokines to attract other immune cells to site of infection and cause inflammation

39
Q

what are dendritic cells

A

reside in tissues that have contact with the outside environment (skin, linings of nose), are phagocytic and APC’s, move through the body via lymphatic vessels to lymph glands where they act as APC’s to the adaptive immunity cells. secrete antiviral cytokines.

40
Q

what are eosinophils

A

release cytotoxic chemicals from granules onto the surface of their targets. also release cytokines to attract other immune cells to site of inflammation. key in defense against larger parasites. phagocytic.

41
Q

what are natural killer cells

A

contain granules that are filled with cytotoxic chemicals like perforin which punch holes in cell membranes and trigger apoptosis. recognize and attack cells that don’t contain self markers.

42
Q

what are mast cells

A

found in connective tissues close to the external environment and known as “border guards”. raise the alarm that a pathogen has entered the body. contain granules containing histamine and other active molecules which are released during inflammation. involved in early recognition of pathogens and releases chemical signals that attract other immune cells to the infection site

43
Q

what are complement proteins

A

a group of proteins dissolved in plasma of blood that helps phagocytes recognise foreign antigens. circulate the body in inactive form until they are activated by an antigen or a signal from an immune cell. once activated they adhere to the invading microorganism making it more readily identifiable as foreign so phagocytes will be attracted to site of infection (opsonisation). “complement” the function of immune cells through a series of biochemical reactions

44
Q

what are interferons

A

a type of cytokine that is released by cells infected with viruses to signal other nearby cells to heighten their antiviral defences, interferons attract natural killer cells to the site to release cytotoxins to kill the infected cell and activate macrophages to clean up the cell debris after lysis of infected cell.

45
Q

what is an antigen

A

a pathogen is an organism that can cause sickness or disease in another organism. it is a unique molecule/part of a molecule that is recognised by the immune system and can initiate an immune response.

46
Q

what are antigens made of

A

protein based and are composed of one or more polypeptide chain. however some can be composed of carbohydrates, lipids or nucleic acids

47
Q

what are self antigens/self markers

A

antigens expressed by cells belonging to an organism (have originated from that organism)

48
Q

what are non-self antigens

A

antigens that have not originated from an organism and therefore do not belong to that organism

49
Q

where are MHC I markers found

A

on surfaces of all nucleated cells of your body (all exept RBC)

50
Q

where are MHC II markers found

A

only on the cell surfaces of special white blood cells known as professional antigen presenting cells- macrophages, dendritic cells and B cells.

51
Q

what does MHC proteins stand for

A

Major Histocompatibility complex proteins

52
Q

what is the process of phagocytosis

A

1- phagocyte activated by chemicals the microbe gives off
2- adherence of pathogens antigen to phagocyte induces membrane protrusions to extend around microbe
3- microbe fully enclosed in a membrane results in phagosome
4- as phagosome moves into cell interior, lysosomes bind with phagosome to form phagolysosome
5- enzymes, like lysozyme, break down and digest microbe
6- formation of residual body with undigested material
7- discharge of undigested material by exocytosis

53
Q

what do APCs do

A

display fragments of digested antigens from foreign. non/self substance on their MHC II markers, on the surface if their plasma membranes. signal to the third line of defense

54
Q

what are cellular pathogens

A

pathogens that have a cellular structure and are capable of reproducing without the use of a host cell

55
Q

what are the cellular pathogens

A

parasites, protozoa, fungi and prokaryotes

56
Q

what is an example of a parasite

A

tapeworm

57
Q

what is non-cellular pathogens

A

dont have a cellular structure and need a host cell in order to reproduce

58
Q

what are the non-cellular pathogens

A

viruses and prions

59
Q

where are endotoxins derived from

A

the outer membrane of gram negative bacteria which are only released when hese bacteria doe and their outer membrane breaks down

60
Q

what are symptoms of bacteria cellular pathogens

A

chills, fevers, weakness

61
Q

how are exotoxins produced

A

by living bacteria when they metabolise they are released into their surroundings

62
Q

what are exotoxins

A

highly toxic soluble proteins

63
Q

what does bacteria have for protection

A

external capsule

64
Q

how does bacteria replicate

A

binary fission

65
Q

how do protists reproduce

A

binary fission

66
Q

symptoms of protists pathogens

A

headaches, muscle aches, tiredness

67
Q

how does fungi reproduce

A

spore formation

68
Q

can parasites live without a host

A

no

69
Q

what are anthropods

A

multilcellular invertebrates with exoskeleton.
reproduce asexually with stages of life. e.g. lice

70
Q

what are comycetes

A

unicellular. penetrate living cells and release molecules that suppress hosts innate immune response. e.g. cinnamon fungus

71
Q

what are viruses called outside of a host

A

virion/ viral particle

72
Q

can viruses metabolise their own energy

A

no and they cannot reproduce without a host cell

73
Q

how does a virus invade a cell

A

1- virus enters cell
2- substances in the cell begin to strip off the viruses outer coat of protein
3- nucleic acid in center of virus is released
4- nucleic acid gets into the cells chemical manufacturing system
5- cell ‘ignores’ its own chemical needs and switches to making new viruses.
6- the cell is sometimes destroyed in the process. many of the new viruses are released to infect other cells.

74
Q

when are prions produced

A

when a normal cellular protein is converted to an infectious, harmful form due to incorrect folding

75
Q

what are virioids composed of

A

short, circular strands of RNA.

76
Q

what is an allergen

A

any antigen that elicits an allergic response.

77
Q

what is an allergic reaction

A

an immune response in which immune system overreacts to a normally harmless substance.