3. implantation Flashcards
what’s the difference between gestational and embryonic age
gest: time zero = first day of LMP
embrace: zero = fertilisation
when does implantation begin. and finsh
begins day 6/7
completed by day 10 (4 days after start)
what are the three main stages of implantation
apposition
attachment
penetration
describe the layers of the trophoblast
inner layer - cytotrophoblast (mononuclear)
outer: SYNCITIOtrophoblast (multinuclear)
lacunae = fluid-filled spaces between
what changes is haemochorial placentation defined by?
- endometrium differentiate into decide: stromal cells and uNK
- opening of uterine spiral arteries
what is the end of the second week characterised by?
first appearance of chorionic villi
primary villous with mesenchymal cores –> secondary
mesen. cells differentiate into tertiary villi (blood capillaries)
how does the embryonic heart connect with the vessels from the villi?
via vessels that differentiate in the mesenchyme of the chorion and connecting stalk
by the 4th month, what are the two main components
maternal portion - formed by decidual plate
fetal portion - formed by chorion frondiosum
what are 3 neural crest disorders
neurofibromatosis
Hirschsprung’s disease
neuroblastoma
name 2 neural tube defects
spina bifida
anencephaly
what week does the brain develop
7th
CNS congenital abnormality where the forebrain fails to divide and develop
holoprosencephaly
what is cardiogenesis
determination of mesoderm and neural crest
differentiate to become cardiomyocytes
what happens in D18-22 of cardiogenesis
- canalisation of cardiogenic clusters in mesoderm
- formation of paired heart tube
- lateral folding fuses tubes in midline
name 2 GI abnormalities
omphalocoele
gastroschisis
