M: Development (Gastrulation)

Question 1

Prior to fertilization, the mammalian oocyte is released from the ovaries and swept by the ____________ to the oviduct

Answer 1

fimbriae

Question 2

Mammals exhibit ______________ cleavage

Answer 2

rotational cleavage

Question 2

Cleavage in mammalian embryo are _____, occuring in the ________

Answer 2

-slow
-uterus

Question 2

__________ initiate the first cell division, and inhibits the protein ___

Answer 2

-Micro RNAs
-Bcl-2

Question 2

Fertilization occurs in the _______ of the oviduct

Answer 2

ampulla

Question 3

Mammalian Cleavage: cell division is ________

Answer 3

asynchronous

Question 4

____________ are activated during cleavage

Answer 4

Zygotic genes

Question 4

New DNA methylation patterns are established for _________

Answer 4

pluripotency

Question 4

Cell adhesion proteins such as ___________ become expressed after the 8-cell stage and the blastomeres become compact

Answer 4

E-cadherin

Question 4

The outside cells form ________-, the cells on the inside form ________

Answer 4

-tight junctions
-gap junctions

Question 5

Yap protein activates the ______________, which transcribes Cdx2 and eomesodermin (the inner cells expresses Lats, a gene that phosphorylates Yap)

Answer 5

Tead4 transcription factor

Question 5

Pluripotency of the ICM is maintained by the _______________

Answer 5

Oct4, Sox2, and Nanog genes

Question 6

The embryo contains genes for transcription of the _______ and the __________-

Answer 6

-ICM (Oct4)
-trophoblast (Cdx2)

Question 6

The cells of the compacted 8-cell embryo produce a 16-cell _______; the external cells become ________(becomes the choroin of the placenta) and the internal cells become the inner cell mass, resulting in a _________

Answer 6

-morula
-trophoblast
-blastocyst

Question 6

Cdx2 is regulated by the _______–

Answer 6

Yap protein,

Question 7

By the _________ stage, the ICM and trophoblast cells become separate layers

Answer 7

64-cell

Question 7

To implant in the uterus, the blastocyst must hatch from the zona pellucida by secreting a ___________-

Answer 7

trypsin-like protease

Question 8

The _________, altered by estrogen and progesterone, has an extracellular matrix that catches the blastocyst

Answer 8

endometrium

Question 8

The expanding blastocoel positions the ICM on one side, forming the ___________

Answer 8

mammalian blastocyst

Question 8

Trophoblast cells create the _________by secreting fluid and pumping sodium, leading to water accumulation

Answer 8

blastocoel

Question 8

The blastocyst expands within the zona pellucida during its journey through the oviduct to prevent adherence to the _______-

Answer 8

oviduct walls

Question 9

The trophoblast synthesizes ______and ___________to bind to the uterine lining

Answer 9

integrins and heparan sulfate proteoglycan

Question 9

___________- instruct the trophoblast to secrete proteases to digest the extracellular matrix and allow the blastocyst to implant in the uterine wall

Answer 9

Wnt proteins

Question 9

forms the yolk sac and does not provide any cells to the embryo

Answer 9

Primitive envelope

Question 9

Epiblast and primitive endoderm form the ___________

Answer 9

bilaminar germ disc

Question 9

The inner cell mass forms the :

Answer 9

-primitive endoderm (lower layer) - epiblast (upper layer)

Question 9

Blastomeres of the inner cell mass at ___________ is a mosaic of epiblast (expressing Nanog transcription factor) and primitive endoderm cells (expressing Gata6 transcription factor)

Answer 9

16-32 cell stage

Question 10

Primitive endoderm cells line the blastocoel to give rise to the yolk sac, those that contact the epiblast are ____________ while those that contact the trophoblast are visceral endoderm____________

Answer 10

-visceral endoderm -visceral endoderm

Question 11

Epiblast layer forms the _____________-

Answer 11

amnion and fills with amniotic fluid

Question 11

Mammalian endoderm and mesoderm cells originate in the ___________

Answer 11

epiblast (primitive streak)

Question 11

mammalian endodern and mesodern undergo ________________-, lose E-cadherin, and migrate through a primitive streak as individual mesenchymal cells to undergo gastrulation

Answer 11

epithelial-mesenchymal transition

Question 11

Gastrulation begins at the____________ where the node forms; __________ arises from the node

Answer 11

- posterior end of the embryo -notochord

Question 11

Cell migration and specification are mediated by __________________

Answer 11

fibroblast growth factors

Question 11

_______________- originate anteriorly to the fully extended primitive streak

Answer 11

Ectodermal cells

Question 12

_____________________ patterns the anterior-posterior axis

Answer 12

Anterior VIsceral Endoderm

Question 12

________ is released by primitive streak to release _______________, forming mesoderm and endoderm;

Answer 12

-BMP4 -Wnt3a and Nodal

Question 12

Twins can either be _________________

Answer 12

monozygotic or dizygotic

Question 12

Once axis was formed, the node secretes _________, the head process

Answer 12

Chordin

Question 13

a result of two separate fertilization events

Answer 13

Dizygotic twins

Question 13

a result of a single embryo that dissociated from one another

Answer 13

Monozygotic twins

Question 14

-Created during gastrulation -If there is a tear at the marginal zone of the epiblast, a second axis can form and express Nodal

Answer 14

Conjoined Twins