510-2 : Introductory Embryology Flashcards
the ___ is a 16-cell solid ball that forms ___ days post- fertilization. what happens in before the division into 16 blastomere cells occurs.
MORULA, 3 days, COMPACTION occurs - developing many tight junctions that maximize the contact b/w blastomere cells. communication of inner cells thru gap jxns and activaiotn of surface cell receptors bein to coordinat e process of differentiating into embryonic tissues.
What is the egg and sperm fusion called?
ZYGOTE
what is the zygote called after it undergoes its first cell cleavage into 2-cells?
EMBRYO = earliest stage of the embryo is a 2-cell stage embryo.
a zygote initially contains a haploid (1N) male and female ____, each of which replicates its DNA and soon after the zygote divides mitotically into 2 _(1N/2N)__ cells.
pronucleus, diploid (2N)
____ is the process that occurs after the 8-cell stage of the embryo and before the 16- cell stage embryo. It consolidates the blastomere cells closer together by developing numerous tight junctions that maximize contact among cells.
COMPACTION
____ & ____ signaling mechanisms are responsible for development and differentiation. ___ signaling means a cell release a cytokine that affects itself, while ___ signaling means a cell releases a cytoking that affects nearby target cells.
AUTOCRINE, PARACRINE, Autocrine, Paracrine
What happens after the compacted 8-cell embryo divides into a 16-cell morula solid ball? what does it form?
morula absorbs fluid inside inner cavity to form the BLASTOCYST
inner cell mass of blastocyst is called the ___ and will develop into the ___.
embyroblast, embryo
cells that surround the blastocyst are called ____ and develop into the _____.
trophoblast, placenta (remember your Trophy is a Placenta)
when the morula absorbs fluid to become a blastocyst, what is the fluid-filled inner cavity called?
primary yolk sac, aka primitive yolk sac
the word morula literally means in Latin : ____
“a little mulberry”
T/F - cleavage of the zygote from 2 cells to 16 (morula) results in an increase in the size of the embryo.
F - the blastomere cells become smaller with each mitotic division, AND they undergo COMPACTION before becoming a morula by developing many tight jxns.
does the oocyte finish its 2nd meiotic division BEFORE or AFTER a spermatozoon enters it.
AFTER
when the oocyte finishes its 2nd meiotic divisoin, one daughter cell is very small and called the ___ ___ ___, while the larger daugher cell is called the ___ oocyte.
second polar body, definitive
T/F - the male and female pronuclei are 1N (haploid) and they swell and replicate their DNA to give rise to a 4N zygote that divides mitotically into 2 diploid (2N) cells.
T
how long does it take for a 2-cell zygote to become a 16-cell morula?
about 3 days
the ___ is the source of the 3 germ layers (510-3 slide 35) . the epiblasts move (due to signals from the primitive node) towards the hypoblasts; some (blue) epiblasts embed in the hypoblast layer (yellow). this innermost hypoblast layer becomes the endoderm. the outer blue layer of epiblasts becoems the ectoderm; epiblasts that get caught in the space in between epiblasts and hypoblasts become the mesoderm. this inward cell migration along the primitive streak is controlled by the gene for _______ ( ).
fibroblast growth factor 8 (FGF 8)
the epiblasts that move inward along the primitive streak are directed by commander cells in the ____ _____.
primitive node
the movement of the primitive streak is anteriorly along the midline, from _____ to _____, towards the (head) buccopharyngeal membrane that later temporarily covers the mouth (stomodeum).
caudal (tail), rostral (head)
the ___ tube is the basis for the dvlpmnt of the CNS.
neural tube
improper or incomplete closure of the neural tube can result in ____, which is when the cranial area doesn’t close and is not viable, or can result in ____ ____, which is when the sacral area doesn’t close. ___ ____ involves a sac at the sacral lower back region that is filled with CSF and can be viable, and this is completely preventable with sufficient dietary ___ ____ in the mother’s diet before the first __ days of development.
ANENCEPHALY, SPINA BIFIDA, SPINA BIFIDA, folic acid, 28
mesoderm on either side of the neural tube organizes into paired segments called ___, which develop into dermis, muscle, tendon, bone of the body wall and limbs.
SOMITES
