Chapter 3 Flashcards
(24 cards)
extraembryonic structures formed in second week
amniotic cavity, amnion, umbilical vesicle (yolk sac), connecting stalk, chorioic sac
implantation occurs in what time range
6-10 days after ovulation (restricted time period)
pinopodes
microvilli of endometrial cells
factors making endometrium favorable to implantation
pinopodes, cell adhesion molecules, cytokines, prostaglandins, homeobox genes, growth factors, and matrix metallo-proteins
connective tissue cells around implantation site do what
accumulate glycogen and lipids, assume polyhedral appearance
embryonic disc layers
epiblast - thick layer of high columnar cells related to amnionic cavity; hypoblast - small cuboidal cells adjacent exocoelomic cavity
embryotroph
fluid in lacunar spaces (formed from maternal blood and cellular debris fom eroded uterine glands); provides nourishment
10-day human conceptus
completely embedded in the endometrium (closing plug present for 2 days)
12-day embryo
adjacent syncytiotrophoblastic lacunae fuse to form lacunar networks; gives sponglike appearance; primordia of intervillous spaces of placenta
extraembryonic coelomic spaces
fuse to form extraembryonic coelom; surrounds amnion and unbilicle vesicle
secondary unbilical vesicle
extraembryonic endodermal cells that migrate from hypoblast inside primary umbilical vesicle; yolk sac
umbilicle vesicle functions
site of origin of primordial germ cells; may have a role in selective transfer of nutrients to embryo
primary chorionic villi
end of second week
extraembryonic coelom splits extraembryonic mesoderm into 2 layers
extraembryonic somatic mesoderm and splanchnic mesoderm
extraembryonic somatic mesoderm
lining the trophoblast and covering amnion
extraembryonic splanchnic mesoderm
surrounding umbilical vesicle
chorion is formed by
extraembryonic somatic mesoderm and two layers of trophoblast
14-day embryo
flat bilaminar disc, hypoblastic cells in a localized area are columnar and form a thickened circular area (prechordal plate)
percent ectopic pregnancies in uterine tubes
95-98 percent
what can pain from ectopic regnancy be confused with
appendicitis
why do ectopic pregnancies (sometimes) give false negatives
rate of Beta-human chorionic gonadotropin production is slower
why is bleeding a big problem in ectopic pregnancies
extensive anastomoses between ovarian and uterine vessels
risk of maternal death by hemorrage in abdominal pregnancies
increases by a factor of 90 compared to intrauterine and factor of 7 compared to tubal
placenta previa
placenta tha partially of completely covers internal Os
