Explains how sperm and oocyte fuse to form a zygote, beginning with sperm travel to the ampulla and the capacitation changes that make fertilisation possible. It then sets out the three phases of penetration and membrane fusion, the formation and merging of the pronuclei, and the main results such as diploid restoration and sex determination. A short closing section lists assisted reproductive techniques (IVF, GIFT, ZIFT and ICSI) with brief notes on each.
Topic 50 of 59 in the MU Pleven syllabus for Cytology (Medicine, Year 1). The free AceMed note covers it in 5 sections, about 383 words (3 min of reading), with 13 flashcards.
In this note
Topic 50. Fertilisation
Phases of Fertilisation
Formation of Pronuclei
Main Results of Fertilisation
Assisted Reproductive Techniques
Topic 50. Fertilisation
Fertilisation is the process by which male and female gametes fuse to form a zygote.
Occurs in the ampulla of the uterine tube.
Preceded by insemination – introduction of sperm into the female reproductive tract.
Only about 1% of sperm deposited in the vagina enter the cervix.
Of 200–300 million sperm, only 300–500 reach the ampulla, the site of fertilisation.
The trip from cervix to oviduct may be as fast as 30 minutes or as long as 6 days.
Sperm are guided by chemotropic factors from cumulus cells around the oocyte.
Only capacitated spermatozoa are capable of fertilising the oocyte.
Capacitation
Removal of glycoprotein coat and seminal plasma proteins from sperm head.
