[LE2] Lecture 10 Flashcards
(106 cards)
1
Q
Distinct feature of mammals: ________________
A
mammary glands
2
Q
Mammals are divided into 2:
A
- Monotremes (egg-laying mammals)
- Placental mammals
3
Q
_____ are usually used as models
A
Mice
4
Q
- Difference: presence of the ________________
- Connected to the _________
A
umbilical cord
placenta
5
Q
- Where there is an interchange of maternal and fetal portion
- Nutrients of maternal blood goes to fetal side
A
Placenta
6
Q
All 4 extraembryonic membranes are still present:
A
yolk sac
chorion
amnion
allantois
7
Q
MAMMALS AS EMBRYONIC MODEL:
- Internal fertilization and development
- _________ must be sacrificed to harvest embryos
A
Mother
8
Q
MAMMALS AS EMBRYONIC MODEL:
_____ embryos produced with lengthy development periods
A
Few
9
Q
MAMMALS AS EMBRYONIC MODEL:
Some early development can be viewed in in _______ culture systems
Mice and pigs are commonly used
A
vitro
10
Q
- _______________ is sometimes used in mice
- Flushing water in the uterus to take out the embryo
A
Uterine washing
11
Q
Very tiny egg and meiosis is not completed until _____________
A
fertilization
12
Q
- Different from other types of cleavage
- There is no direct connection between the ________ to the uterine duct
- During ovulation, the ___________ needs to catch the ovulated ovum and have it fertilized if sperm is available
- In the area of the infundibulum
A
ovary
fimbriae
13
Q
If fertilized, as the embryo moves down to be implanted in the uterus, the cleavage and other early stages of the blastula or the _________ is developing
A
morula
14
Q
Blastulas are called ___________ in mammals
A
blastocysts
15
Q
The _____________ usually found in a blastula is not present as a coelom separating the epiblast and hypoblast
A
blastocoel
16
Q
____________________ entails that new embryo must be protected before it can be implanted
A
Internal fertilization
17
Q
_________________ protects and prevents pre-implanting (ectopic pregnancy)
A
Zona pellucida
18
Q
UNIQUE MAMMALIAN CLEAVAGE - _________________ (describe)
A
Holoblastic, rotational
Slower and asynchronous
19
Q
1st cleavage: normal, meridional ___________ plane
A
cleavage
20
Q
2nd cleavage: one blastomere meridional, one _____________ equatorial
A
blastomere
21
Q
- Embryonic gene expression occurs right away
- There is no ___________ transition
■ No maternal genes required for midblastula transition (gene expression during this phase)
A
midblastula
22
Q
It should be ensured that all genes would have already been __________ and _____________ reprogramming have already been accomplished
A
methylated
epigenetic
23
Q
After the 3rd cleavage (8 cells), _______________ express large amounts of adhesion molecules, like E-cadherins (uvomorulin)
A
blastomeres
24
Q
Cells become a ________, __________ ball of cells
■ inner cells sealed off from outside environment (mother’s body is also considered foreign because of difference in ______________)
A
tight, compact
compositions
25
- At the 16-cell stage, embryo becomes a __________
- Small group of cells inside surrounded by a layer of eternal cells
morula
26
As the morula develops, a fluid
filled cavity forms (_______________)
________________ forms on one side and cells become compacted on the other side
Blastocoel
27
Cells on the outside are called ______________ and become extraembryonic membranes (chorion) and embryonic portion of the placenta
trophoblast
28
Cells on the inside are called __________________ and produce the embryo proper and the other extraembryonic membranes (yolk sac, allantois, and amnion)
inner cell mass
29
Trophoblast secretes fluid into the morula stimulated by _________ cells
oviduct
30
- Trophoblast cells contains _______________
- Water goes into the cavity following the _________ gradient
Na pumps (Na+-K+ ATPase and the Na+-H+ exchanger)
osmotic
31
Inner cell mass is positioned on one side of the ring of trophoblast cells resulting to a ____________ and not a blastula
blastocyst
32
_____________ endoderm becomes hypoblast in amphibians and mammals
Primitive
33
__________________ doesn't become part of embryo and only counts as an extraembryonic membrane
Trophectoderm
34
_________ allows for the transcription of Cdx2 which allows for the production of trophoblast-specifying genes
○ Eomes
○ Psx1
○ Hand1
Tead4
35
(one ans)
● Genes will help specify trophoblast cells
● Higher differentiation signals include the ____
● In trophoblast cells, _____ signal is destroyed
● ____ prevents Lats from cleaving the Yap
hippo
36
Without being cleaved, Yap binds to Tead4 which
allows for the transcription of _______
Cdx2
37
If Hippo (a transmembrane protein) allows Lats to
_______________ Yap, which destroys Yap, Yap will not be able to bind to Tead4 which prevents transcription of Cdx2
phosphorylate
38
Transcription of embryonic genes are happening
early on during the ________ stage
morula
39
Oct4 and Sox2 function for the production of ______ cell genes and _________
ICM, Nanog
40
Nanog has an ____________ response. Nanog allows more Nanog to be produced
autocrine
41
Oct4, Sox2, and Nanog are all needed for _____ production
ICM
42
(one ans)
In another view, Oct4 and Sox2 would allow for _______________ of themselves
Nanog could allow ______________ for all three
self-regulation
43
_______________ for ICM is maintained when all three
are present
Pluripotency
44
HIPPO SIGNALING:
● _______ can inhibit Yap or Taz
● Those in apostrophe(?) can be similar to
drosophila = drosophila signals
● In ICM cell, _______ will not be bound by Yap/Taz
LATS
Tead
45
Oct4 allows __________________ cell to become further a part of either oocyte or spermatocyte
development
primordial germ
46
If the inner cell mass, after being informed of becoming ICM, uses Oct4, then it becomes the __________
epiblast
47
Yap/Taz becomes part of the _________________
Trophectoderm
48
- _______ = Hippo signaling (found in ICM)
- ______________ are needed to ensure that the morula is compacted
Amot
E-cadherins
49
- Hippo signaling allows for _______________________
- Equivalent of diagram with no unknown signal in basis for trophoblast formation
Hippo-kinase cascade
50
THE CRUCIAL ROLE OF ZONA PELLUCIDA:
- It prevents the _________________ of the zygote in the uterus or the uterine tube
- Prevents _______________
early implantation
ectopic pregnancy
51
Blastocyst initially has 2 groups of cells:
○ Trophoblast
○ Inner cell mass
52
Trophoblast -> cytotrophoblast -> __________________
syncytiotrophoblast
53
Part of extraembryonic membrane which will be the ___________
becomes part of the __________ as it implants in the uterus
chorion
placenta
54
Inner cell mass will become ____________ endoderm
(hypoblast). Becomes part of ____________
primitive
yolk sac
55
- Inner cell mass will become ___________
- Part of __________ ectoderm (will be fluid-filled)
epiblast
amniotic
56
Divides into embryonic ectoderm and primitive streak
Embryonic epiblast
57
_________________ divides into embryonic endoderm, embryonic mesoderm, and extraembryonic mesoderm
Primitive streak
58
Oct4, Sox2, and Nanog are all found together with the _____________ to fuse together in the ICM
e-cadherins
59
Cdx2 and e-cadherins on the _________
outside
60
(one ans)
● Aside from Nanog, there is also a presence of
____
● Eventually, ____ will be found outside together with Laminin; below ICM is ____ with e-cadherins
Gata6
61
Within embryo, there is high concentration of Nanog, Oct4, and Sox2 which will be the _________________
inner cell mass
62
● Cdx2 and e-cadherins on ______________
● Even if there is movement, the gene expression in ICM area is still the ________
trophoblast
same
63
● Cells internalized from stages 8-16 = becomes __________
● Cells internalized from stages 16-32 = becomes __________
● Nanog and Gata6 moved to their new locations and form the ____________
epiblast
hypoblast
blastocyst
64
● ________ is present in all areas = allows binding of all layers together
● ________ is found in all areas
● No ________ in parietal endoderm area
laminin
gata6
cdh1
65
● Initially, there is a formation of a _____________________
● _____________ disc is formed when the three germ layers are already present
bilaminar germ disc
Trilaminar
66
As there is shifting and formation of _____________, the maternal and fetal side is distinguished allowing for exchange of nutrients
placenta
67
FGF8 (and its receptors) is to drive the ________________ out of the streak
mesendoderm
68
Fgf8 may also control _____________________ by regulating snail, Brachyury, and Tbx6, three genes that are essential (as they are in the chick embryo) for mesodermal migration, specification, and patterning
cell specification
69
There is a formation of the node and movement of the ________________
The primitive groove, as the ______ is moving, is also allowing the internalization of the mesoderm and endoderm ; hypoblast moves towards the side
primitive groove
node
70
Snail, Brachyury, and Tbx6 allows for ____________ migration (epiblast is renamed and endoderm is below)
mesoderm
71
Epithelial-mesenchymal transitions at the primitive streak precedes ____________ of the mesoderm.
ingression
72
Thickened bulb at the anterior end of the primitive streak
THE MAMMALIAN NODE
73
Analogous to the amphibian ________________ and the chick Hensen's node
trunk organizer
74
[THE MAMMALIAN NODE]
Gives rise to the ____________. Cells forming the ___________ gets integrated into the endoderm of the primitive gut
notochord
75
Axis and notochord formation in the mouse.
● _________ - neural induction and A-P axis
●__________ - positioning of the primitive streak
node
AVE
76
The anterior size will be having the expression of the ____________; (similar in amphibians and birds)
Cerberus
77
Prechordal mesoderm will become the ____________
notochord
78
● _________ from extraembryonic ectoderm instructs epiblasts to make Wnt3a and Nodal
● _________ secretes antagonists Lefty-1, Dickkopf, and Cerberus -> no effect on anterior end
BMP4
AVE
79
Wnt3a activates Brachyury in posterior epiblasts - generates ______________ cells
mesodermal
80
Node secretes Chordin and the head process and notochord secretes __________ -> promotes formation of the forebrain, nose, and other facial structures
Noggin
81
Formation of the AVE precursor cells by __________________ in the mouse embryo.
mechanical stress
82
_____ AND _______ ACID GRADIENTS:
Anterior-posterior patterning in the mouse embryo.
FGF and Retinoic
83
Evolutionary conservation of homeotic gene organization and transcriptional expression in fruit flies and mice is seen in the similarity between the Hom-C cluster on _____________ chromosome 3 and the four Hox gene clusters in the mouse genome.
Drosophila
84
[L-R AXIS FORMATION]
● Genes:
○ Left side: ________ and _______
○ Right side: ____________ inhibiting Nodal
nodal and pitx2
cerberus
85
- __________ cells of the node allows movement in a clockwise direction
- __________ deficiency prevents L-R axis
Ciliary
Dynein
86
_________ cells detect movement and activates Pkd2 which suppresses Cerberus
Crown
87
● Fetuses of the same sex
● Share one placenta
● One outer membrane envelops both amniotic sacs
Identical Twins
88
● Fetuses may be of different sex
● Two placentae
● Two separate amniotic sacs, each with its own membrane
Fraternal Twins
89
SUMMARY OF MAMMALIAN DEVELOPMENT:
early cleave: _______ cleavage
late cleavage:
early gastrula:
late gastrula:
pharyngula:
equal holoblastic
extraembryonic ectoderm, epiblast, hypoblast
mammalian node
correct arrangement of 3 germ layers
characteristic vertebrate
90
What kind of cleavage amphibians?
holoblastic, mesolecithal, displaced radial cleavage
91
What kind of cleavage mammals?
holoblastic, isolecithal, rotational cleavage
92
What kind of cleavage birds, reptiles?
meoblastic, telolecithal, discoidal cleavage
93
MAJOR THEMES OF GASTRULATION:
1. Internalization of the ___________ and _____________
2. ___________ of the ectoderm around the entire embryo
3. Convergence of the _________ cells to the midline
4. Extension of the body along the ________________ axis
1. endoderm, mesoderm
2. Epiboly
3. internal
4. anterior-posterior
94
Produces any cells from one
Cell proliferation
95
Creates cells with different characteristics at different positions
Cell specialization
96
Coordinate the behavior of each cell with that of its neighbors
Cell interaction
97
Rearranges the cells to form structured tissues and organs
Cell movement
98
MOLECULAR SIGNALS FOR AXIS FORMATION
● A-P Axis: _____ genes
Hox genes
99
Anterior Axis: ______ inhibition and _______- expression
wnt and otx 2
100
Posterior Axis: ________ and _____ proteins
nodal and wnt
101
D-V Axis:
Dorsal Axis: _____ inhibitors
Ventral Axis: BMPs
BMP
102
L-R Axis: Nodal activating ____
Pitx2
103
[Amphibians]
cleavage:
nieuwkoop center:
organizer:
unequal, holoblastic
dorsal-most vegetal cells
dorsal blastoporal lip
104
[Fishes]
cleavage:
nieuwkoop center:
organizer:
discoidal meroblastic
yolk syncytial layer
embryonic shield
105
[Avians]
cleavage:
nieuwkoop center:
organizer:
discoidal, meroblastic
posterior marginal zone
hensen's node
106
[Mammals]
cleavage:
organizer:
equal holoblastic
mammalian node
