L7 - Growth and Cancer Flashcards Preview

BMS247 Stem Cells > L7 - Growth and Cancer > Flashcards

Flashcards in L7 - Growth and Cancer Deck (62)
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1
Q

What must occur before growth can occur

A

Patterning over a small scale

2
Q

How does differential growth account for differences in the limb in bats and humans

A

Have the same humerus - radius/ulna - digits

But in bats these are elongated to a much greater degree

3
Q

3 methods of growth

A

Cell proliferation
Cell enlargement
Accretion

4
Q

Cell proliferation AKA

A

Hyperplasia

5
Q

Cell enlargement AKA

A

Hypertrophy

6
Q

What drives G1 phase

A

Cdk4/6 and cyclin D

7
Q

What drives G1/S

A

Cdk2 and cyclin E

8
Q

What drives S/G2

A

Cdk2 and cyclin A

9
Q

What phase of the cell cycle do terminally differnetiated cells enter

A

Quiescent

10
Q

Early drosophila embryo is a

A

Synctiium (single multinucleate cell)

11
Q

Describe the cell cycle in the early divisions of the drosophila embryo

A

Rapid synchronous cycles of only S and M phases

12
Q

Describe what is seen at the 14th cycle

A

Slowing of the cycle and introduction of G2 phase

13
Q

What is the division rate in the drosophila embryo determined by

A

Location of that cell

14
Q

Groups of cells with similar fates may have similar division rates - what is term used to describe this

A

Mitotic domains

15
Q

Cell division in mitotic domains is controlled by what protein

A

String

16
Q

During the first 13 division describe the distribution of string

A

Uniformly distributed owing to its maternal origins

This allows for the rapid synchronous divisions

17
Q

Describe the distripution of string after the first 13 division

A

Zygotically expressed string produced under the direct control of the patterning genes

18
Q

What happens in the mesoderm to string and why?

A

Tribble blocks string

Mesoderm must first involute before any growth can occur

19
Q

Describe what would happen if there was an additional thymus gland - what ype of control is this

A

All organs maintain their size and multiple ammounts of tissue will be present
INTRINSIC CONTROL

20
Q

Describe what would happen if there was an additional spleen - what type of control is this

A

Both would grow to half the size such that the total ammount of spleen tissue remains the same

SYSTEMIC CONTROL

21
Q

What pathway controls the size of the cell

A

TOR pathway

22
Q

What pathway limits the size of organs

A

Hippo pathway

23
Q

Describe the hippo pathway when it is inactive

A

TF Yki/Yap/Taz is in the nucleus which stimulates growth and promotes the survival of cells

24
Q

Describe the hippo pathway when it is active

A

Transcritpion factor Yki/Yap/Taz excluded from the nucleus and growth is inhibited

25
Q

What factors lead to the activation of the hippo pathway

What is the result of this activation

A

Cell cell contact
Cell polarisation

Activation of pathway leads to inhibition of grwoth

26
Q

What factors lead to the inactivation of the hippo pathway

A

Mechanical stress - because there are not enough cells so this causes some cells to become streched
Other signalling pathways

27
Q

Describe a hippo mutant version of the fly imaginal disc

A

Mutant disc much bigger in size
Yki is in the nucelus
Ability to restrict growth has been lost

28
Q

Describe a hippo mutant liver

A

Mutant much bigger
Yap/Taz in the nucleus
Ability to restrict growth of cells has been lost

29
Q

Name an example of a area where growth rate is not unifrom

A

Head

30
Q

Why are pygmess shorter

A

Second growth spurt doesnt happen

31
Q

Size of the adult fly determined by

A

Size of the larva

32
Q

What affects duration and rate of fly larval growth

A

Insulin

33
Q

When the larva reaches a certain size what occurs

A

Metamorphosis

34
Q

What induces metamorphosis in the fly

A

Edcyson

35
Q

What are the main determinants in the difference in size of dogs

A

IGF and GH pathways

36
Q

What hormones control growth in mammals

A

GF1 GF2 IGF1 IGF2

37
Q

Production of growth hormone in the pituritry activated by

A

GHRH (growth hormone releasing hormone)

Somatostatin

38
Q

What is the main site for IGF production

A

Liver

39
Q

What an example of how maternal environment can affect growth

A

Shetland cross shire horse

If mother is the Shetland then the foal is smaller

40
Q

Compare the signals used for development and then during post embryonic development

A

Dev - short range and small
Post emb dev - influences from the environment act on the CNS which then produces hormones which act at the scale of the whole organism

41
Q

Molting is AKA

A

Ecdysis

42
Q

Why must motling occur

A

Since cuticle is rigid and doesnt allow for much growth to occur

43
Q

Intermolds are refereed to as

A

Instars

44
Q

Molting initiated by

A

Activtion of strech receptors in the cuticle

45
Q

Once strech receptors have been activated what occurs next

A

Release of protothoracicotrophic hormone from the corpus alatum

46
Q

Release of protothoracicotrophic hormone leads to _________________________

This leads to

A

Ecdyson from the prothoracic gland

Molting then occurs under influecne of ecdyson

47
Q

Describe the process of molting

A

First cuticle separates from the epidermis
While original cuticle is still present freed epidermal cells prolfierate and secrete a fluid forming a barrier which begins then secreting a new cuticle - only after this will the old cuticle be shead

48
Q

What prevents metomorphosis in flies

A

Ecydyson

49
Q

What causes ecdyson release - where is it released from

A

Brain releases prothoracicotrophic hormone which then acts on the prothoracic gland causes the release of ecdyson

50
Q

Describe how metamorphosis is triggered in frogs

A

Hypthalmus releases CRH
acts of the pituitrary to release of TSH
Causes the thyroid to release thyroxin (T3 T4)

51
Q

What delays metamorphosis in frogs

A

Prolactin

52
Q

Cancer is essentially the

A

Loss of growth control

53
Q

Where is cancer most common

A

In already proliferating cells - such as epithelia

54
Q

What are teratomas

A

Cancer cells which give rise to tissues of all 3 germ layers

55
Q

Protooncogenes

A

Once activated become oncogenes
Genes that can cause cell division
Ras Raf EGFR Myc

56
Q

Tumour supressior genes

A

Once inactive cause cancer
Usually decrease the rate of cell division
E.g. Rb, P53, ptc, APC, VHL

57
Q

Type of cancer caused by abberent Wnt

A

Colon cancer

Hepatocellular cancer

58
Q

Type of cancer caused by abberent Hh

A

BCC

Medulloblastoma

59
Q

Type of cancer caused by abberent Nodal

A

Melanoma

60
Q

Type of cancer caused by abberent Notch

A

Leukaemia

61
Q

Type of cancer caused by abberent EGF

A

Lung cancer

Breast cancer

62
Q

Describe dominantly inherited cancer syndromes

A

TSGS at the centre
Two hit hypothesis
If inherit a faulty copy of the gene
Easier then for the remianing copy to become damaged