Social cells

Question 1

how do cells interact with each other?

Answer 1

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

Question 2

signalling molecule?

Answer 2

the ligand

Question 3

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

Answer 3

on cell to cell communication

Question 4

ligands?

Answer 4

the signalling molecules released by the cell to communicate

Question 5

receptors?

Answer 5

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

Question 6

examples of short distance communication?

Answer 6

contact-dependent (juxtacrine)
autocrine signalling
paracrine signalling

Question 7

examples of long distance communication?

Answer 7

synaptic and endocrine signalling

Question 8

juxta?

Answer 8

near

Question 9

auto?

Answer 9

self

Question 10

para?

Answer 10

beside

Question 11

endo?

Answer 11

within (the body)

Question 12

contact-dependent communication example?

Answer 12

immune response

Question 13

autocrine signalling example?

Answer 13

proteins, RNAa etc

Question 14

paracrine signalling example?

Answer 14

proteins RNAs etc,

Question 15

examples of synaptic communication?

Answer 15

neurotransmitters

Question 16

examples of endocrine signalling communication:

Answer 16

hormones

Question 17

krine?

Answer 17

secrete (or separate)

Question 18

describe endocrine signalling:

Answer 18

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

Question 19

describe synaptic signalling:

Answer 19

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

Question 20

describe paracrine signalling:

Answer 20

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

Question 21

What distance is endocrine signalling?

Answer 21

long distance

Question 22

what are some diseases associated with hormonal deficiency?

Answer 22

diabetes
osteoporosis
reproduction and infertility
growth retardation

Question 23

ligands in paracrine signalling

Answer 23

produced in low levels and quite tightly controlled

Question 24

antagonist and inhibitors?

Answer 24

two ways to interfere with signalling

Question 25

antagonist

Answer 25

blocking receptors

Question 26

inhibition

Answer 26

stopping signal from getting out

Question 27

what is the distance with paracrine signalling?

Answer 27

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

Question 28

What are disease associated with defects in paracrine signalling?

Answer 28

inflammation and allergies

Question 29

structure of histamine?

Answer 29

amino acid derivative

Question 30

source of histamines?

Answer 30

mast cells

Question 31

actions of histamines?

Answer 31

vasodilation contracts airways

Question 32

local mediators messengers?

Answer 32

histamines, thromboxane, leukotrienes

Question 33

structure of thromboxane?

Answer 33

lipid derivative

Question 34

structure of leukotrienes?

Answer 34

lipid derivatives

Question 35

source of thromboxane?

Answer 35

blood platelets

Question 36

source of leukotrienes?

Answer 36

inflammatory cells

Question 37

actions of thromboxane?

Answer 37

vasconstriction causes platelet aggregation

Question 38

actions of leukotrienes?

Answer 38

constrict airways attract inflammatory cells make blood vessels leaky

Question 39

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

Answer 39

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

Question 40

describe how membrane proteins on each cell interact:

Answer 40

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

Question 41

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

Answer 41

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

Question 42

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

Answer 42

gap junctions allowing contraction of cardiac cells or propagating electrical synapses

Question 43

slide 15

Question 43

what is synaptic signalling?

Answer 43

it is technically short distance but allows rapid long distance signalling

Question 44

what do the vast majority of signalling molecules bind to?

Answer 44

receptors

Question 44

what does the ligand-receptor interaction promote?

Answer 44

promotes a conformational change in the receptor

Question 45

where are most of the receptors situated?

Answer 45

on the plasma membrane but some can be intracellular

Question 45

what can some messengers do?

Answer 45

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

Question 46

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

Answer 46

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

Question 47

different cells contain different...?

Answer 47

different pools of receptors or different concentration of receptors

Question 48

19,20

Question 49

what are ligands?

Answer 49

hormones

Question 50

meaning of lipophilic?

Answer 50

tending to combine with or dissolve in lipids or fats

Question 51

what tends to be lipophilic?

Answer 51

the hormones in the endocrine signalling

Question 52

explain how endocrine signalling is very specific?

Answer 52

only cells/organs presenting appropriate receptors will be influenced

Question 53

what can start a paracrine signalling?

Answer 53

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

Question 54

describe the concentration of the ligands in paracrine signalling:

Answer 54

it is usually low and can be controlled in several ways

Question 55

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

Answer 55

enzymes ECM antagonists inhibitors

Question 56

what is autocrine signalling?

Answer 56

the cell signalling to itself

Question 57

what ligands promote autocrine signalling?

Answer 57

cytokines growth factors hormones

Question 58

what can autocrine signalling do?

Answer 58

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

Question 59

how is autocrine signalling used - in context?

Answer 59

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

Question 60

what is juxtacrine signalling also known as?

Answer 60

contact dependent signalling

Question 61

what is juxtacrine signalling?

Answer 61

signalling directly between two cells via direct contact

Question 62

describe what the distance is of synaptic signalling?

Answer 62

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

Question 63

what does synaptic signalling do?

Answer 63

coordinate the behaviour of cells far apart from each other

Question 64

what does synaptic signalling do to electrical impulses?

Answer 64

they are transformed into chemical signals

Question 65

what does synaptic signalling occur between?

Answer 65

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

Question 66

what do the vast majority of signalling molecules bind to?

Answer 66

receptors

Question 67

what can some messengers bind to?

Answer 67

ion channels or they can cause synthesis of a second messenger

Question 68

what is a competent cell?

Answer 68

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

Question 69

one messenger can activate...

Answer 69

different isoforms of the same receptor, inducing different biological effects

Question 70

one receptor can bind...

Answer 70

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

Question 71

signal amplification?

Answer 71

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

Question 72

what are the four main types of receptors?

Answer 72

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

Question 73

what type of receptor is ion-channel coupled receptors?

Answer 73

ionotropic receptors

Question 74

what is different about the four main receptors?

Answer 74

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

Question 75

nuclear receptors are...

Answer 75

intracellular

Question 76

what do G-proteins coupled receptors carry out?

Answer 76

metabotropic transmission

Question 77

what is the main type of enzyme coupled receptors?

Answer 77

tyrosine kinase

Question 78

gap junctions?

Answer 78

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

Question 79

what signalling is local?

Answer 79

paracrine signalling and synaptic signalling