Lecture 13: The Bilaminar Embryo Flashcards Preview

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Flashcards in Lecture 13: The Bilaminar Embryo Deck (22):
1

three germ tissue types

Ectoderm, mesoderm, endoderm

2

Morula

ball of cells, 32 or after 5 divisions. still embryonic stem cells. As the cells divide, migrate down the fallopian tube towards the uterus

3

Blastocyst

Morula transforms into this by secreting a fluid within the ball, creating a blastocyst cavity. Creates a polar ball, with one highly cellular side and one a-cellular side. Contains embryoblast and trophoblast

4

embryoblast

inner cell mass of blastocyst

5

trophoblast

outer cell wall of blastocyst

6

when does zona pellucida break down?

when blastocyst develops, this allows for implantation

7

When is implantation

5-7 days after fertilization, during the blastocyst phase

8

which side of blastocyst approaches uterus

the side with inner cell mass

9

Syntiotrophoblast

The trophoblast cells invade the endometrium during implantation, in the process become syntiotrophoblast, a multi-nucleated mass that invade the endometrium wall, forming connections with maternal capillaries and glands that will lead to lacunar network. Also release human chorionic gonadotropin, which promotes the LC to continue releasing progesterone which continues pregnancy

10

cytotrophoblast

what remaining trophoblasts differentiate into during implantation, are the surrounding cells of blastocyst after implantation

11

exocoelemic cavity

what blastocyst cavity is called post-implantation. lined with exocoelemic membrane

12

hypoblast cells

line the roof of the exocoelemic cavity, what bottom of inner cell mass embryoblasts differentiates into. Seen as primitive endoderm

13

epiblast

line the amniotic cavity that forms within the former inner cell mass of former blastocyst. primitive ectoderm

14

amniotic cavity

forms within former inner cavity of blastocyst, lined by amnion (membrane)

15

bilaminar embryo

the epiblasts and hypoblasts together form the bilaminar embryo or bilaminar disk

16

heuser's membrane

other name for exocoelemic membrane, created by migrating hypoblasts from roof of cavity.

17

Primary Yolk Sac

develops from exocoelemic membrane and cavity, exocoelemic membrane now called primary yolk sac endoderm

18

extraembryonic mesoderm

Surrounds amniotic cavity and primary yolk sac and bilaminar embryo, is created by primary yolk sac endoderm

19

Extraembryonic coelem

Spaces form in extraembryonic mesoderm, resulting in extraembryonic coelem surrounding primary yolk sac

20

extraembryonic splanchnic vs. somatic mesoderm

E. splanchnic mesoderm surrounds primary/secondary yolk sac, E. somatic mesoderm lines the extraembryonic coelem

21

Secondary yolk sac

formed when part of primary yolk sac is pinched off to temporarily be within the extraembryonic somatic mesoderm before degenerating. The secondary (or definitive) yolk sac serves as site of early transfer of nutrients, health blood development, and provides primordial germ cells

22

prechordal plate

Develops as thickened area of hypoblasts in a localized area of bilaminar embryo, determines chordal-caudal polarity, site of mouth