VAP > Early Development > Flashcards

Early Development Flashcards

(57 cards)

Study These Flashcards
1
Q

what three general things does the development process involve?

A
  • pattern
  • specialisation
  • growth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

morula

A

Formed from a fertilised egg going through a series of regulated cleavages to form a compact ball of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

cleavage stage

A

fertilised egg forms a morula (only no. of cells increases, size of egg remains)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

compaction

A

outer cells in a morula begin to flatten and adhere tightly together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the first specialisation decision?

A
  • outer cells of the morula flatten and become more compact
  • greater adhesion than inner cells
  • leads to outer cells forming trophoblast in blastocyst when fluid moves into the morula therefore forming placental membranes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what would happen if an outer morula cell is transplanted into the middle of another embryo?

A

the cell would move back to the outside as it has specific plasma membrane proteins that distinguish it from inner cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how is a blastocyst formed?

A
  • fluid begins to enter the late morula
  • fluid accumulates between them due to differences in the adhesion of the outer and inner cells forming a fluid filled cavity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the fluid filled cavity of a blastocyst called?

A

blastocoel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the two parts of a blastocyst?

A
  • ICM (inner cell mass)
  • trophoblast
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the roles of the ICM and the trophoblast?

A
  • ICM forms embryo
  • trophoblast forms placental membranes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what happens during implantation and hatching?

A
  • zygote arrives in the uterus from the fallopian tubes
  • outer cells secret an enzyme that digests the outer coat (hatching)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how and when is the placenta formed?

A
  • placenta is formed after the hatching blastula is implanted
  • outer trophoblast cells begin to proliferate and become further specialised to form placenta
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what does the ICM form in the bilaminar disc?

A
  • epiblast
  • hypoblast
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

the epiblast and hypoblast form a division in the blastocyst, what are the two sections called? (and which side of the division are they on?)

A
  • amniotic cavity (on epiblast side)
  • blastocoel/yolk sac (on hypoblast side)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the second specialisation decision?

A

formation of the epiblast or hypoblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

give two pieces of evidence that the definitive embryo pattern is not present in the blastocyst?

A
  • blastocysts can be cloned and form two complete individuals as long as ICM is present
  • cells can be transplanted between blastocysts and the embryo displays traits from both groups of cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what may influence the organisation of the embryo in a blastocyst?

A

entry-point of the sperm may influence subsequent cleavages therefore the organisation of the embryo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

bilaminar disc

A

the distinct two layered embryonic structure (epiblast and hypoblast)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what three things does gastrulation achieve?

A
  • head-tail axis (primitive streak)
  • inside-outside specialisation (germ layers)
  • left-right axis (primitive streak)
  • rostral-caudal axis (primitive node)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how can you show that the epiblast forms the embryo?

A
  • add markers to the epiblast cells
  • embryo cells should show the markers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is gastrulation?

A

the migration of cells from the epiblast to form a three layered structure (and displacing the hypoblast)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are the three germ layers?

A
  • endoderm
  • mesoderm
  • ectoderm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

which structures are formed at the caudal and cranial ends of the epiblast in gastrulation?

Study These Flashcards
A
  • primitive streak (caudal end)
  • primitive node formed from extension of primitive streak (cranial end)
24
Q

what defines the cranial-caudal axis and the left-right axis of a bilaminar disc?

Study These Flashcards
A
  • primitive streak
25
primitive pit
circular depression (dip) formed from the primitive node
26
primitive groove
primitive pit extends towards the caudal end to form a primitive groove
27
how are the three germ layers formed?
- cells move down the primitive groove, detach from the epiblast and slip between the epiblast and hypoblast (invagination) - this displaces and replaces the hypoblast to form the endoderm - remaining epiblast cells form ectoderm - some epiblast cells remain in the space between the ecto and the endoderm to form the mesoderm - epiblast cells stop migrating once formed - process continues across the disc from caudal to cranial end
28
trilaminar disc
embryonic disc with the three primary germ layers (ectoderm, mesoderm, endoderm)
29
what does the ectoderm form?
- CNS - PNS - epidermis
30
what does the mesoderm form?
- muscles - bones - kidneys - reproductive system - blood vascular system - peritoneal linings - dermis
31
what does the endoderm form?
- intestine linings - liver - pancreas - lung lining - respiratory tract - thymus/parathyroid
32
what does each germ layer vaguely form?
ectoderm - skin and nervous system mesoderm - muscle, bone, blood, kidney etc endoderm - gut
33
what is special about the oral and cloacal regions of the primitive streak?
- endoderm and ectoderm remain in contact (no mesoderm) - oral region forms at anterior/primitive node end - cloacal regions forms at posterior end
34
what is the evidence to show that Hensen's (primitive) node organises the main body axis?
if Hensen's node is grafted from an embryo to a host embryo then the new axis is induced in the host (second organism grows)
35
how is the neural tube formed?
- notochord secretes paracrine signalling proteins - neural plate forms neural groove (dips) - neural crest forms between ectoderm and neural groove - neural tube seals off and neural crest detached
36
which direction does the neural tube closure move in?
begins near rostral end and progresses caudally
37
what is the evidence to show that the notochord conveys information to the ectoderm to induce the neural tube to form?
- transplantation of a second notochord leads to a second neural tube - any ectoderm transplanted next to the notochord will be induced and form neural tissue
38
notochord
rod-like structure found in the mesoderm of vertebrates (disintegrates later on)
39
what is spinal dysraphism?
term that covers various types of problems that occur in the spine and neural tube of foetus
40
which species and breed are genetically predisposed to spinal dysraphism? and what form of spinal dysraphism are they predisposed to?
- Weimaraner dogs - spina bifida
41
spina bifida
neural tube not completely closed (leading to a gap in spine)
42
anencephaly
neural tube does not close completely and parts of skull and brain are missing
43
how can neural tube defects be minimised?
- optimising intake of folic acid and cholesterol levels - cholesterol may be important in the processing of a secreted protein (Sonic Hedgehog)
44
zona pellucida
protective coat surrounding the early zygote whilst it is in the fallopian tubes (before hatching and implantation)
45
which cavity forms between the hypoblast and the trophoblast?
yolk sac
46
which cavity forms between the epiblast and the trophoblast?
amniotic cavity
47
three sections of the mesoderm from the primitive streak outwards
- axial mesoderm - paraxial mesoderm - intermediate mesoderm - lateral plate mesoderm
48
what does the paraxial mesoderm form?
somites
49
what does the intermediate mesoderm form?
- kidney - gonad
50
what does the lateral plate mesoderm form?
- blood - peritoneum
51
what determines the cranio-caudal body axis?
Hensen's node
52
what does the axial mesoderm form?
notochord
53
what does the notochord form?
nucleus pulposis (centre of vertebrae)
54
what forms the neural tube and what stimulates its formation?
- notochord secretes signalling proteins - induce specialisation of ectoderm cells to form floor of neural tube
55
two pieces of evidence that the mesoderm (axial) conveys information to the ectoderm for neural tube development
- if a second notochord is transplanted alongside the first, a neural tube develops with a duplicated structure - if any ectoderm is transplanted next to the axial mesoderm, it will be induced to form the neural tube
56
what do neural crest cells form?
- PNS - melanocytes - facial structures - heart valves
57
neural crest
as the neural groove joins, the leading cells break off to form two neural crests either side above the neural tube
VAP
flashcards
Decks in class (25)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions