Specification: Mammals (lec 17) Flashcards
During its migration to the uterus, the ____ ______ prevents the embryo from prematurely adhering to the ______.
Zona pellucida; oviduct
(T/F) Cleavage occurs as the embryo travels to the uterus after fertilization.
True!
What kind of cleavage do echinoderms and amphibians undergo compared to mammals?
echinoderms and amphibians: radial cleavage
mammals: rotational cleavage
What is inner cell mass (ICM)?
the portion of the blastocyst of a mammalian embryo that is destined to become the embryo as it contains embryonic stem cells
From morula to blastocyst, the three principal cell types are: _______, _______, and ______ _____.
Trophectoderm; Epiblast; Primitive endoderm (hypoblast)
*epiblast becomes the embryo
In a ___________ circuit, the ____/____ dimers activate the Nanog genes.
Nanog proteins then activate _____ ___ as well as genes promoting ________.
Feedforward, Oct4/SOx2
Its own gene; Pluripotency (ICM cell genes)
(T/F) Oct4, Sox2, and Nanog are part of an interconnected regulatory circuit in which they activate themselves and each other’s synthesis.
True!
Match the EXTRAEMBRYONIC tissues to their definitions:
1) Syncytiotrophoblast
2) Extraembryonic endoderm
3) Amniotic ectoderm
4) Extraembryonic mesoderm
A) Forms the yolk sac needed for nutrition before the placenta forms
B) Lines the chorion, amnion, yolk sac and contributes to blood formation and umbilical cord
C) Will ingress into the uterine tissue to form the CHORION (contributes to the placenta)
D) Encircles the amniotic cavity
Syncytiotrophoblast: Will ingress into the uterine tissue to form the CHORION (contributes to the placenta)
Extraembryonic endoderm: Forms the YOLK SAC needed for nutrition before the placenta forms
Amniotic ectoderm: Encircles the amniotic cavity
Extraembryonic mesoderm: Lines the chorion, amnion, yolk sac and contributes to blood formation and umbilical cord
The blastocyst gives rise to:
Trophoblast and Inner cell mass
The syncytiotrophoblast rises from:
The extraembryonic endoderm rises from:
The amniotic ectoderm rises from:
The extraembryonic mesoderm rises from:
The syncytiotrophoblast rises from: TROPHOBLAST
The extraembryonic endoderm rises from: Primitive endoderm (hypoblast)
The amniotic ectoderm rises from: Epiblast
The extraembryonic mesoderm rises from: Primitive streak
(T/F) Primitive streak gives rise to the embryonic mesoderm, endoderm, and ectoderm.
True!
What happens at days 14, 15 and 16 during human gastrulation?
At days 14 and 15, the ingressing epiblast cells are thought to replace the hypoblast cells (which contribute to the yolk sac lining).
At day 16, the ingressing cells fan out to form the MESODERMAL LAYER.
Following multiple rounds of whole genome duplication, vertebrates have multiple ____ clusters.
Hox
*there is evolutionary conservation of hox genes from flies to mammals
(T/F) Hox genes give identities and are very important for the anterior-posterior regionalization of our spines.
True!
The chick has TWICE AS MANY _____ _______ as the mouse.
CERVICAL VERTEBRAE