Social cells Flashcards

cell to cell communication

1
Q

how do cells interact with each other?

A

by releasing extracellular molecules influencing the behaviour of their neighbour or more distant cells

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2
Q

signalling molecule?

A

the ligand

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3
Q

what does cell growth, differentiation metabolism and death depend on?

A

on cell to cell communication

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4
Q

ligands?

A

the signalling molecules released by the cell to communicate

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5
Q

receptors?

A

the receiving molecules capable of translating the extracellular signal into an intracellular modification

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6
Q

examples of short distance communication?

A

contact-dependent (juxtacrine)
autocrine signalling
paracrine signalling

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7
Q

examples of long distance communication?

A

synaptic and endocrine signalling

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8
Q

juxta?

A

near

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9
Q

auto?

A

self

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10
Q

para?

A

beside

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11
Q

endo?

A

within (the body)

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12
Q

contact-dependent communication example?

A

immune response

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13
Q

autocrine signalling example?

A

proteins, RNAa etc

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14
Q

paracrine signalling example?

A

proteins RNAs etc,

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15
Q

examples of synaptic communication?

A

neurotransmitters

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16
Q

examples of endocrine signalling communication:

A

hormones

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17
Q

krine?

A

secrete (or separate)

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18
Q

describe endocrine signalling:

A

hormones - slow diffusion in the bloodstream - days to have an effect

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19
Q

describe synaptic signalling:

A

neurotransmitters, 100m/sec for the electrical impulse
millisec for the release/uptake of neurotransmitters

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20
Q

describe paracrine signalling:

A

local mediator, proteins RNAs sugars, gases, lipids
local mediator controls speed of message delivery

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21
Q

What distance is endocrine signalling?

A

long distance

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22
Q

what are some diseases associated with hormonal deficiency?

A

diabetes
osteoporosis
reproduction and infertility
growth retardation

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23
Q

ligands in paracrine signalling

A

produced in low levels and quite tightly controlled

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24
Q

antagonist and inhibitors?

A

two ways to interfere with signalling

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25
Q

antagonist

A

blocking receptors

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26
Q

inhibition

A

stopping signal from getting out

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27
Q

what is the distance with paracrine signalling?

A

short distance cell-to-cell communication - the exact distance is not quantified

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28
Q

What are disease associated with defects in paracrine signalling?

A

inflammation and allergies

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29
Q

structure of histamine?

A

amino acid derivative

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30
Q

source of histamines?

A

mast cells

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31
Q

actions of histamines?

A

vasodilation
contracts airways

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32
Q

local mediators messengers?

A

histamines, thromboxane, leukotrienes

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33
Q

structure of thromboxane?

A

lipid derivative

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34
Q

structure of leukotrienes?

A

lipid derivatives

35
Q

source of thromboxane?

A

blood platelets

36
Q

source of leukotrienes?

A

inflammatory cells

37
Q

actions of thromboxane?

A

vasconstriction
causes platelet aggregation

38
Q

actions of leukotrienes?

A

constrict airways
attract inflammatory cells
make blood vessels leaky

39
Q

what are the 3 forms of juxtacrine/contact dependent signalling?

A

membrane proteins on each cell interact
membrane proteins interact with part of an extracellular matrix
junctions link cells allowing small molecules to pass between

40
Q

describe how membrane proteins on each cell interact:

A

antigen presenting cells trigeering differentiation of types of T cell into Th or Tc

41
Q

describe how membrane proteins interact with part of an extracellular matrix:

A

integrins and RTKs allowing interaction with ECM to regulate processes such as cell division

42
Q

describe how junctions link cells allowing small molecules to pass between?

A

gap junctions allowing contraction of cardiac cells or propagating electrical synapses

43
Q

slide 15

A
43
Q

what is synaptic signalling?

A

it is technically short distance but allows rapid long distance signalling

44
Q

what do the vast majority of signalling molecules bind to?

A

receptors

44
Q

what does the ligand-receptor interaction promote?

A

promotes a conformational change in the receptor

45
Q

where are most of the receptors situated?

A

on the plasma membrane but some can be intracellular

45
Q

what can some messengers do?

A

they can also bind ion channels or cause the synthesis of a second messenger

46
Q

what does the cell need to do in order to pass on the message?

A

the cell needs to express the right receptors for the messenger to pass on the message (competent cell)

47
Q

different cells contain different…?

A

different pools of receptors or different concentration of receptors

48
Q

19,20

A
49
Q

what are ligands?

A

hormones

50
Q

meaning of lipophilic?

A

tending to combine with or dissolve in lipids or fats

51
Q

what tends to be lipophilic?

A

the hormones in the endocrine signalling

52
Q

explain how endocrine signalling is very specific?

A

only cells/organs presenting appropriate receptors will be influenced

53
Q

what can start a paracrine signalling?

A

a vast range of different ligands: growth factors, gases and inflammatory mediators

54
Q

describe the concentration of the ligands in paracrine signalling:

A

it is usually low and can be controlled in several ways

55
Q

how can the concentration of ligands be controlled in paracrine signalling?

A

enzymes
ECM
antagonists
inhibitors

56
Q

what is autocrine signalling?

A

the cell signalling to itself

57
Q

what ligands promote autocrine signalling?

A

cytokines
growth factors
hormones

58
Q

what can autocrine signalling do?

A

it can decrease or promote the signalling initiated by the cell itself (negative or positive feedback effect)

59
Q

how is autocrine signalling used - in context?

A

it is one way cancer cells can promote their own survival and division

60
Q

what is juxtacrine signalling also known as?

A

contact dependent signalling

61
Q

what is juxtacrine signalling?

A

signalling directly between two cells via direct contact

62
Q

describe what the distance is of synaptic signalling?

A

it is technically short distance but it does allow rapid long distance signalling

63
Q

what does synaptic signalling do?

A

coordinate the behaviour of cells far apart from each other

64
Q

what does synaptic signalling do to electrical impulses?

A

they are transformed into chemical signals

65
Q

what does synaptic signalling occur between?

A

it is very specific, between neurons, between sensor and neuron or between neuron and effector cell

66
Q

what do the vast majority of signalling molecules bind to?

A

receptors

67
Q

what can some messengers bind to?

A

ion channels or they can cause synthesis of a second messenger

68
Q

what is a competent cell?

A

a cell that needs to express the right receptor for the messenger to pass on the message

69
Q

one messenger can activate…

A

different isoforms of the same receptor, inducing different biological effects

70
Q

one receptor can bind…

A

different ligands and with different affinity, again mediating different biological effects

71
Q

signal amplification?

A

there can be an amplification of the signal within the cell and cross-talk between different signalling cascades

72
Q

what are the four main types of receptors?

A

ion channel coupled receptors
G-protein coupled receptors
Enzyme coupled receptors
Nuclear receptors

73
Q

what type of receptor is ion-channel coupled receptors?

A

ionotropic receptors

74
Q

what is different about the four main receptors?

A

they have different molecular structures ans they work at different speeds and/or for different lengths of times

75
Q

nuclear receptors are…

A

intracellular

76
Q

what do G-proteins coupled receptors carry out?

A

metabotropic transmission

77
Q

what is the main type of enzyme coupled receptors?

A

tyrosine kinase

78
Q

gap junctions?

A

like plasmodesmata in plant cells
they are connections between two close cells that allow ion/other small molecules to pass - so they don’t have to pass across the cell membrane

79
Q

what signalling is local?

A

paracrine signalling
and synaptic signalling

80
Q
A