week 4 Flashcards
Cell division that produces gametes- will have ½ normal somatic chromosomes components (Sex cells)
meiosis
of cells & chromosomes in meiosis
4 cells 23 chrom
division of a single cell that produces 2 identical cells with the same number of chromosomes
mitosis
Allows random assortment of maternal and paternal chromosomes between the gametes
meiosis
of cells and chromosomes in mitosis
2 cells, 46 chromosomes
What is the role of Zona Pellucida
sperm binding and protetction
Where does fertilization taking place
ampulla portion of Fallopian tubes
What does the term zygote means?
fertilized ovum
What gamete determinate gender of the human offspring
sperm
What is the name of the dividing cell right after conception
zygote
What happen during cleavage
- Mitosis is occurring and the cells are doubling in numbers
- Implantation completes cleavage
What does term morula mean?
16 cells produced after 4 rounds of cell division
Name the parts of blastocyst at the time of implantation.
- inner cell mass
- blastocyst cavity
- trophoblast
At what time after fertilization dose implantation begin?
6 days after fertilization
Gametogenesis is ___
part of meiosis
in oogenesis @ ovulation is the start of___
second meiotic devision
when ___ occurs the second meiotic division is completed.
fertilization
follicular cells protective layer.
corona radiata
Fertilization takes place 24 to 12-24 hours after ___
ovulation
1st cleavage completes about ___ after ___
- 30-40 hrs
- fertilization
1st mitotic division yields 2___
blastomeres
Cell division resulting in smaller and smaller cells is termed
cleavage
____ begins 24 to 30 hours after fertilization
mitosis
4-5 days post fertilization fluid passes into the morula and is termed
blastocyst
trophoblast becomes the ___ and the fetal contribution to the placenta
chorion
inner cell mass becomes the ___
embryo, amnion, cord, and secondary yolk sac
in uterus, the blastocyst receives nutrients from ___
endometrial glands
___ completes the period of cleavage
implantation
during implantation trophoblast differentiates into 2 layers:
- cytotrophoblast
2. syncytiotrophoblase
___ invades the endometrium to from lacunae spaces
syncytiotrophoblast
outer multicelled layer of trophoblast with finger like projections
syncytiotrophoblase
Single cell inner layer forms the chorion
cytotrophoblast
T/F: implantation involves both endometrium & myometrium
FALSE- only endo
Primary function is the production of hCG to extend the life of the corpus luteum
trophoblast
Implantation that occurs where there is no endometrial lining is called
ectopic preg
blastocyst inner cell mass epiblast form the
amnionic cavity which secretes fluid
forms the primary umbilical vesicle aka primary yolk sac
hypoblast
within the ___ fluid spaces form to create the chorionic cavity
extraembryonic coelom
chorion surrounds the chorionic cavity and is made up of ___ and __ cells
- mesoderm
- trophoblast
also known as gestational sac
chorionic sac
1st sonographic evidence of an intrauterine pregnancy
GESTATIONAL SAC
umbilical vesicles produce ___ and nourish ___
- first blood cells
- conceptus
bilaminal embryonic disk has initially 2 layers ___ & ___
endoderm (inner) & ectoderm (outer)
biliminar converts to triliminar by ____
gastrulation
triliminar layers include
- endoderm
- mesoderm
- ectoderm
amnion is adjacent to the ___ (back of trilinimar disc)
ectoderm
yolk sac is adjacent to the ___ (infront of triliminar disc)
endoderm
T/F: all fetal tissues arise from grastulation triliminar layers
true
when cells migrate from hypoblast to create mesoderm b/w endo and ectoderm
primitive streak
endometrial layers
- decidua capsularis
- decidua parietalis
- decidua basalis
closes over and surrounds the burrowing blastocyst (developing embryo)
decidua capsularis
lines the rest of the endometrial cavity which is not implanted by the blastocyst
decidua parietalis
the area that the blastocyst attaches to the uterus and goes on to contribute to the maternal portion of the placenta
decidua basalis
implantation of embryo
- blastocyst attach and imbed in decidua
- blastocyst is imbeded in deepest layer decidua basalis whwere trophoblast proliferate. capsularis surround the blastocyst and pareitalis is on opposite side of uterine cavity
- gestational sac grows, contour of decidua caps distorts uterine cav
what creates the double decidual sign
decidual caps & pareitalis
maternal blood supply to placenta via
villi
blood drained from placenta via
endometrial vein
placenta produces
- chronic gonadotropin
- estrogen
- progesterone
pregnancy test measure ___ levels
B-HCG
B-HCG produced by ___ until 10 weeks then placenta takes over
syncytiotrophoblasts
PRIMIGRAVIDA
pregnant for the first time
term for organogenesis 6-10 weeks LMP
EMBRYO
NULLIGRAVIDA
never been pregs
connects yolk sac to embryonic midgut
VITELLINE DUCT
1st trimester
LMP-13 weeks
2nd trimester
14wk-27 wks
3rd trimester
28 wk- term (40 weeks)
NORMAL PREGNANCY = ___ WEEKS / ___ DAYS
40 WEEKS / 280 DAYS
EDC
estimated date of confinement
EDD
estimated date of delivery