Early Embryology Flashcards
When is the egg released from the ovary?
14 days into ovarian cycle
What is sperm travel from cervix to oviduct?
30 mins to 6 days
What is the egg coat called?
Zona pellucida
What is the female nucleus called?
Female pronucleus
What is the male nucleus called?
Male pronucleus
3 things that happen during fertilization
- Diploid number of chromosomes
- Gender determination
- Cleavage initiated
The sperm has to meet the egg cell within ___ hours of ovulation
24
At what point does the cell become a 2 cell stage zygote?
30 hours
What is the ball of cells called after the zygote rapidly divide?
Morula
At what point does cell become a morula?
3 days
At what point does the morula become an advanced morula?
4 days
What is the next stage after morula?
Blastocyst (fluid filled cavity)
When does the blastocyst form?
5 days post-fertilization
What mass develops in blastocyst?
Inner cell mass (embryoblast)
When does blastocyst enter uterus?
4.5-5 days
When does blastocyst implant in endometrium?
5.5-6 days
Development of embryo occurs at _____ from conception
7-8 weeks
List types of abnormal implantation *
Interstitial
Tubul (isthmus)
Tubal (ampullar)
Infundibular (ostial)
Ovarian
Peritoneal
Cervical
At week 1, what tissues are present?
Syncytiotrophoblast
Cytotrophoblast
Inner cell mass
Syncytiotrophoblast has…
Lacunae
Tissue of uterine wall is also known as
Uterine stroma
At week 2, trophoblasts differentiates into 2 layers known as…
The cytotrophoblast and Syncytiotrophoblast
At week 2, the embryoblast forms 2 layers known as
The epiblast and hypoblast
At week 2, 2 cavities form known as the
Amniotic and yolk sac cavities
At week 2, the extraembryonic mesoderm splits into
The somatic and splanchnic layers
At day 8, what parts divide?
Trophoblasts
Embryoblast
Syncytiotrophoblast region is
Multinucleated bc no cell walls
What do Syncytiotrophoblasts produce?
hCG
At day 9, what forms?
2 cavities:
Amniotic cavity
Exocoelomic cavity (primitive yolk sac)
What in the amniotic fluid is important for amniocentesis?
Sloughed off cells from embryo
What procedure do the sloughed off cells from amniotic fluid help us do?
Karyotyping
What occurs at day 12?
Extraembryonic mesoderm becomes somatic and splanchnic layers
What happens on day 13?
Extraembryonic cavity/chorionic cavity becomes huge but will quickly regress by end of second month
At 13 days, what else grows but will quickly regress later?
Yolk sac but by end of second month will regress