Embryology Flashcards
Gestation
The time required for for development of a fetus in uterus
What is a pre-embryonic period
The first two weeks
When is the embryonic period
3 to 8 weeks
When is a foetus formed
9+ weeks
What happens during fertilisation
Female reproductive tract deliver sperm to ampulla of uterine wall
How many hours after ovulation do you sperm and ovum meet
12 to 24 hours in uterine tube
What makes the ovum impermeable to other sperm
Acrosomal reaction- capacitation shedding of acrosomal cap of sperm
Penetration of Corona radiata and Zona pellucide
Without capacitation sperm are incapable
Of penetrating the oocyte
The zygote and its associated membranes- conceptus
Projected Towards uterus by peristalsis and Celia of uterine tubes
What happens during cleavage
Zygote undergoes 5 to 6 rapid mitotic cell divisions
The cavity forms blastocysts
What happens in twins
In non-identical twins the over them splits so is dizygotic, and identical twins the zygote splits and they share a placenta
Formation of blastocyst
16 cell stage – solid sphere of cells called a morula
Differentiation of blastocyst – cavity enlarges, pressure builds and increases number of cells
Changes in uterus in week one
Conceptus floats freely, cells divide, uterine wall thickens, uterine milk secreted, start of implantation signals end of pre-embryonic stage of development
Where does implantation usually takes place
On fundus or posterior wall of body of uterus
Implantation what does trophoblast do
Interact with uterine epithelium
