fertilization

artifical insemination

the introduction of semen to the female genital tracts by artificially placing it into uterus or vagina

uterus structure

uterine neck (yellow)

unterine horns (green)

ovaries (blue)

oviduct (pink)

copulation

sexual intercourse

where does approximation of gametes occur in mammals?

ampulla (part of the oviduct)

where does approximation of gametes occur in birds?

infundibulum (part of the oviduct)

how does the sperm arrive to the oviduct?

it is mobile due to its flagellum, vaginal and uterine contraction, difference in pressure, quimiotaxis (movement due to chemical stimulus)

what is spermatozoa capacitacion?

changes that occur in the sperm to allow it to cross the zona pellucida

what is fertilization?

fusion of egg and sperm

what is required for penetration of sperm to zona pellucida?

spermatocyte and oocyte activation

steps of spermatocyte activation

1. sperm binds with zona pellucida
2. acrosome reaction: enzyme breaks down zona pellucida
3. sperm and oocyte unite and nuclei fuse

steps of oocyte activation

1. cortical reaction: release of cortical granules occur when sperm breaks the zona pellucida
2. the cortical granules block the entrance of other sperm

what type of cell is the new zygote?

diploid

polyspermy block

prevents fertilization by more than one sperm by releasing enzymes that inactivate the sperm receptors and harden the zona pellucida

when does meiosis resume / complete

After sperm entry:

Oocyte resumes meiosis, releasing a second polar body with half the chromosomes.

Oocyte nucleus (haploid) is now ready to combine with the sperm nucleus (haploid).