Embryology 1 Flashcards
What does the spermatogonium produce?
4 sperm
What does the oogonium produce?
1 ova and 3 polar bodies
When does meiosis i occur in females?
Whilst in utero
What is fertilisation?
Pro nucleus of a sperm fuses with the pro nucleus of an ovum to form a zygote (diploid)
The zygote divides to form a solid ball of cells, what is the term used to describes this new structure?
Morula
What does the morula become?
Blastocyst
What are the 3 components of a blastocyst?
Inner cell mass
Blastocystic cavity
Trophoblast
On what day is a blastocyst formed?
5th
How long does the first division of the zygote take?
Approximately 36 hours
How is the zygote able to move?
Ciliated epithelial tissue
How can etopic pregnancy occur?
If cilia function is abnormal
What does the trophoblast form?
Chorion
What are the 3 functions of the chorion?
Implantation process (via chorionic villi)
Forms part of the placenta
Secretes human chorionic gonadotropin (HCG)
How can pregnancy be detected?
Presence of human chorionic gonadotropin (hcg) in blood
What is the role of human chorionic gonadotropin?
It signals to ovary to continue to produce oestrogen and progesterone
What causes morning sickness in pregnancy?
High levels of HCG
What does the inner cells of the blastocyst form?
Bilaminar disc
What are the 2 cavities created by the bilaminar disc?
amniotic sac and yolk sac
What are the 2 layers of the bilaminar disc?
Epiblast and hypoblast
What are the 3 main functions of the placenta?
Exchange gas
Waste
Foetal nutrient
Immune
What are fraternal twins?
2 eggs fertilised by different sperm
What are identical twins?
Develop from a single fertilised egg that splits in two.
