Fertilization Mechanism Flashcards
shell around human egg
zona pellucida (ZP1-4)
The _____ releases the egg from the germinal vesicle and completes meoisis I
LH surge
____ cells surround the ZP
cumulous cells
Capacitation
process that ensures sperm can fertilize an egg –> e.g. motility increase due to cAMP, loss of cholesterol from plasma membrane, chang ein surface charge, change in ion conductance, elevation of intracellular pH
With the help of _____, a cell surface _____, capacitated sperm penetrate the cumulus oophorus
PH20 –> surface hyaluronidase
ZP ___ is most crucial for egg/sperm interaction
ZP3
Only after ____ can the sperm fuse with the egg plasma membrane
acrosomal reaction
____ releases GPI linked proteins from the sperm surface and inner acrosomal matrix in the process of enzymatic hydrolysis of the ZP.
angiotensin converting enzymes
T/F penetration of the ZP requires motile force from sperm.
T –> in addition to enzymatic hydrolysis
____ plane of the sperm head attaches to the plasma membrane of the oocyte during adhesion and membrane fusion
equatorial plane –> 3 hours
Fertilization induced calcium oscillations
early event is increase in egg cytosolic calcium –> triggered by PLC
_______ are released after fertilization to prevent other sperm from penetrating.
cortical granules
At the ___ stage, cell boundaries are not visible anymore due to ____
morula –> compaction
Frequency of polyspermy after ovulation
1-2%
T/F polyspermy may be 30% if mating is delayed after ovulation/aged eggs
T
In humans, where is the block to polyspermy?
level of ZP as well as membrane
Can oocyte activation occur without sperm?
Yes –> parthenogenesis due to mechanical trauma, temperature shock, ICSI, etc.
intrauterine insemination
seminal fluid washed out –> sperm in alkaline buffer for capacitation –> intrauterine insemination
Approximately how long after LH surge will ovulation take place?
36 hours
Indication for intrauterine insemination
mild to moderate male factor infertility
Intracytoplasmic sperm injection (ICSI)
sperm injected into egg directly
