Human Reproduction - Fertilisation Flashcards
How sperm get to ovum
Cervix -> Uterus -> Fallopian tube -> Ovum
Capacitation:
In uterus - sperm interact with hormone/ chemical by female
Makes sperm more active + attract them to ovum - to right fallopian tube
Thins acrosome membrane - acrosome reaction
Process of sperm binding to oocyte
Sperm - corona radiata binding
-burrows through corona radiata
-to zona pellucida
Acrosome reaction
-acrosome break open
-digestive enzyme released to move through
Sperm receptor binding
-sperm bind to receptor on oocyte membrane
-genetic information + centriole released - midpiece detached
Process of sperm binding 2
Completion of Meiosis 2
-when receptor binded oocyte complete meiosis to ovum
-polar body attached is released
Cortical reaction
-when receptor bind, corticle granule release chemical to hardened zona pellucida to prevent polyspermy
Formation of diploid zygote
-chromosome from sperm + egg fuses to become diploid zygote to divide
Zygote -> Blastocyst
Undergo cleavage period
-cells in zygote divide via mitosis
-into many cells (morula)
-zona pellucida maintain volumn of zygote so travel through fallopian tube safely
Blastocyst
Cells in zygote divide unevenly + form fluid inside zygote
Trophoplast
-cell on outer layer
-can differentiate into amnion for amniotic sack
-or into chorion for placenta + umbilical cord
Inner cell mass - stem cells that’s not yet differentiated
Blastocoel cavity - fluid for the formation of amniotic fluid
Secretes hCG - prevent corpus Luteum to not dissolved - keep releasing oestrogen + progesterone
Blastocyst diagram
https://www.institutobernabeu.com/wp-content/uploads/2021/03/ICONO-Fases-blastocisto-IB-EN-1024x1024.jpg
Implantation
Blastocyst implants itself into endometrium wall for nurturers
Chorion - start to form placenta
Amnion - start to form amniotic sac for baby
Amniotic fluid provides safe environment
