Early Embryology Flashcards
ovulation occurs ______ days into the ovarian cycle where 1 ______ is released from the ovary and swept up by fimbriae into the _______
14, oocyte, oviduct (uterine tube/fallopin tube)
the sperm travel time from cervix to oviduct is about ______ to ______
30 min, 6 days
the results of fertilization include a _________, gender ________, and ________ initiation
diploid number of chromosomes, determination, cleavage
fertilization happens when a sperm makes contact with the egg and releases enzymes from its _______ to degrade the _______, then the sperm binds to the egg so that the sperm and egg ________ merge, the egg then releases chemcials to prevent ________, the sperm and egg nuclei then combine to make a ______
acrosome, zona pellucida, membranes, other sperm from entering, diploid zygote
after fertilization the egg and sperm are now considered a single celled ______
zygote
the results of fertilization include the formation of a _______, _______ number of chromosomes, _______ determination, and __________ initiation
zygote, diploid, gender, cleavage
does the sperm or egg determine gender?
sperm
the sperm must reach the egg within 24 hours or it will _______
degenerate
the ______ is the widen part of the uterine tube where the sperm and egg meet and fertilize
ampulla
the purpose of fimbrae is to ______ the oocyte into the_______
sweep, fallopian tube
the myometrium is composed of ______ and is under the endometrium but between the endometrium and perimetrium
smooth muscle
cleavage begins around ____ hours after fertilization
30
the zygote repeatedly divides through mitosis into 2 cells (_______), then 4 cells (_______), then 8 cells, 16 etc and continues
blastula, blastula
once a zygote divides into 16 to 32 cells it is considered a ______
morula
The morula forms after fertilization and multiple cleavages about ____ days after fertilization
3
The morula becomes an advanced morula at around ____ days after fertilization
4
around 5 days post fertilization, the morula forms a hallow ball of cells called ______ that contains _____ in the center
blastocyst, fluid
the inner cell mass of the blastocyst is called the ______
embryoblast
the inner cell mass or embryoblast will eventually become the _______
embryo
the _______ is the inner hollow cavity of the embryoblast
blastocyst cavity/ blastocoele
the blastocyst is pushed along the fallopian tube until it enters the ______ and implants on day 7
uterus
the blastocyst sheds the ________ beofore implantation
zona pellucida
the blastocyst implants into the ______
endometrium
cervical implantation is not ideal due to growth of the fetus causing too much ______ and does not give viable room for growth
pressure
in normal implantation the oocyte moves ______ towards the uterus
proximally
in a peritoneal pregnancy the egg falls out of the fallopian tube and implants on the ______ wall
abdominal
on day 8, the trophoblast differentiates into two layers; the _________ and the _____________
cytotrophoblast, syncytiotrophoblast
the trophoblast is the ________ cells of the blastocyst
surrounding (kinda like a cell wall)
the _______ cells invade the uterine wall for implantation
trophoblast
the trophoblast eventually becomes part of the ______ and provides ______ to the developing embryo
placenta, nutrients
the cytotrophoblast is considered the ______ layer of the trophoblast, and can be thought of as the ______ cells of the trophoblast
**still contain cell walls
inner, stem
during week two the syncytiotrophoblasts start to produce enough ______ to give off a positive pregnancy test
hCG hormone
the syncytiotrophoblast is considered the _____ layer of the trophoblast and is the part that implants into the ______
**lose cell walls
outer, endometrium
on day 8, the embryoblast divides into the ______ and ______
epiblast, hypoblast
on day 9, two cavities form called the ________ and the exocoelomic cavity also called the _______
amniotic cavity, primitive yolk sac
inside the epiblast is where the ________ forms and grows
amniotic cavity
the hypoblasts give rise to the _______
primitive yolk sac
amniocentesis is the process of obtaining _____ in order to test for genetic defects of the developing fetus
amniotic fluid
the amniotic cavity eventually will be the space the ______ develops
fetus
once the yolk sac has been depleted of all the _______, the ______ and _______begin to support the fetus with nutrients
nutrients, placenta, umbilical cord
on day 12 the _______ is split to form the extraembryonic ______ mesoderm and the extraembryonic ______ mesoderm
extraembryonic mesoderm, splanchnic, somatic
the extraembryonic _______ mesoderm is the inner layer closest to the yolk sac that will eventually form ______
splanchnic, internal organs
the extraembryonic ______ mesoderm is the outer layer closer to the trophoblasts that will eventually form ______
somatic, external amenities
On day 13, in between the somatic and splanchnic mesoderms, the ________forms
chronic cavity
the amniotic cavity is the only cavity that will ______
grow
the trophoblastic lacunae or pools of blood can cause women to have a ______
“fake period”
at the start of week 3, gastrulation converts the _________ embryo into the _________ embryo
bilaminar, trilaminar
the three germ layers produced by gastrulation include the _______, ________, and ________
ectoderm, mesoderm, endoderm
the ectoderm is formed from the ______, while the endoderm is formed from the displacement of ______
epiblasts, hypoblasts
the ectoderm forms the ________, ______ and appendages that relate to _______ environments
neural system, skin, external
the mesoderm forms the ________ tissue, ______ buds, _______ system, body wall and membranes that line _______
musculoskeletal, limb, genitourinary, cavities
the endoderm forms the foregut, midgut, and hindgut, the ______ tract, ______ tract and _______
GI, respiratory, bladder
during gastrulation the epiblast cells migrate through the ______ node and streak
primitive
the cloacal membrane will eventually become the _____ while the oropharyngeal membrane will become the future ______
anus, head and mouth
the _______ membrane develops faster/sooner because the cells migrate through the primitive streak toward it
oropharyngael
a teratogen refers to the agent responsible for a ______
birth defect
the disease holoprosencephaly (cyclopia) is usually genetic and associated with gastrulation in that there is an injury to the ________
anterior midline (cranial region) of the germ disc
the disease caudal dysgenesis (sirenomelia) is usually caused by genetic and environmental factors and associated with gastrulation in that there is an injury to the ________
caudal (tail region) aspect of the germ disc
sacrococcygeal tumors are associated with gastrulation due to remnant of the ______….. this forms teratomas which are tumors that can have hair, teeth etc
primitive streak
conjoined twins is associated with gastrulation in that the splitting of the _______ happens to late
primitive node
