Fertilisation To Blastocyst Hatching Flashcards
What are the characteristics of the spermatazoon head?
Devoid cytoplasm
Densely coiled chromatin
Covered by acrosome an plasma membrane
What is the characteristic of the midline e of the spermatazoon?
Tightly coiled regions of mitochondria to fuel flagellum
What are the characteristics of the spermatozoon tail?
Connected by a centriole
Central axoneme
Side - side action
What influences sperm swimming speed?
Contraction of the reproductive tract and prostaglandins
What is Capacitation?
Removal of the protective cell membrane and tail stimulation
What are the three phases of fertilisation?
- Penetration of the corona radiata
- Penetration of the Zona pellucida
- Fusion of the oocyte and spermatozoon
What are the proteins of Zona pellucida and their functions?
ZP1&2 create a mesh or. ZP3 is. Receptor for SED1 that brings about an acrosomal reaction.
WHat occurs during an acrosomal reaction?
Break down of the acrosomal lining of the spermatozoon cell
what breaks down the Zona pellucida?
Acrosin
What does binding of the sperm cell membrane to the oolemma cause?
Membrane depolarisation and calcium ion influx
What does the increase in calcium cause?
A cortical reaction where cortical granules release enzymes to breakdown ZP3. Blocking polyspermy. Meiosis II restarts and the division of the 1st polar body occurs.
What happens to the oocyte after fertilisation?
It is stimulate to finish meiosis II
What is formed through cleavage?
Blastomeres
When does an embryo become a morula?
At the 16 cell stage
What occurs at compaction?
The cells become flattened and polarised as they interact with the Zona pellucida to form the basement membrane. Tight junctions form
