DLA 5 Flashcards
Explain week one of fertilization?
- capacitation
- Acrosome reaction
- Fusion of the membranes between both sex cells
What happens during capacitation?
Removal of the seminal proteins from the surface and penetration through the corona radiata
What happens during acrosome reaction?
Release of acrosomal enzymes and penetration through the zona pellucida
What is the normal site of fertilization?
The ampula of the fallopian tube
How is the normal diploid number gained?
The fusion of the male and female pronuclei
What is the developing embryo called after the formation of 16-32 blastomeres?
Morula (day 3)
What are blastomeres defined as?
The production of identical daughter cells
Explain the formation of the blastocyst?
This occurs after the morula enters the uterus
A blastocystic cavity forms within the morula
The blastomeres separate into two separate parts:
- centrally located cells (embryo) located at the embryonic pole
- peripheral cells (trophoblast)
Where does the blastocyst normally implant itself?
Posterior wall of body of uterus close to the fundus
6 days
How does the blastocyst attach to the endometrium?
By the syncytiotrophoblast
When the blastocyst attaches to the endometrium.. what two layers does the trophoblast differentiate into?
an inner cytotrophoblast
an outer syncytiotrophoblast
What does the inner cytotrophoblast do?
Makes new cells and mitotically active
What does the syncytiotrophoblast?
invades and secretes
human chorionic gonadotrophin (HCG)
can be used to determine pregnancy early
What enables the burrowing of the blastocyst?
mass of cells or syncytium at the embryonic pole erode
