Anatomy (germ layers and differentiation) Flashcards
3 germ layers
ectoderm (external)
mesoderm (middle)
endoderm (internal)
oocyte
a cell in an ovary that may undergo mitotic division to form an ovum
Ovulation
Ovum is released from ovarian follicle
Fertilisation
weeks 1-2
Embryogenesis
weeks 3-8
Fetal development
weeks 8- term
Zona pellicuda
Barrier that coats the ovum, sperm enzymes needed to penetrate
Zygote
egg and sperm together
Hydatidaform mole
Zygote that isn’t activated , little or no embryonic tissue, cystic structure may form
Embryogenesis
formation/ development of embryo
Morula
‘mulberry’ , at day 16
Blastocyst naming
‘blast’- growth/development
‘cyst’- sac or vesicle in body
Blastocyst formation
embryoblast + trophoblast
Embryoblast
the embryo itself - develops into bilaminar disc
Trophoblast
forms the placenta , v invasive
Embryonic stem cells
pluripotent
Ectopic pregnancy
embryo implants outside the uterine cavity
Bilaminar disc
hypoblast
epiblast
Two cavities forming in embryoblast
Yolk sac and amniotic cavity
Primitive streak
appears in epiblast , forms to create third layer
Primitive streaks becomes …
primitive node -> primitive pit -> primitive groove
Organogenesis
by the end of week 8 main organ systems have been established
Gastrulation
the process of forming 3 germ layers
Blastula
early embryonic form produced by cleavage of a zygote
Germ layer
primary layers of cells of the embryo from which the tissues and organs develop
