fertilization of an egg by sperm takes place in water or a moist area.
fertilization of an egg by sperm takes place in water or a moist area.
fertilization of an egg by sperm takes place in the?
in water or a moist area
when sperm cells are deposited into the anterior vagina, they are not capable of fertilization (i.e., non-capacitated) and are characterized by slow linear motility patters. this motility pattern, combined with muscular contractions enables sperm transport towards the uterus and fallopian tubes. there is a ph gradient within the microenvironment of the female reproductive tract such that the ph near the vaginal opening is lower (approximately 5.0) than the fallopian tubes (approximately 8.0). the sperm-specific ph-sensitive calcium transport protein called catsper increases the sperm cell permeability to calcium as it moves further into the reproductive tract. intracellular calcium influx contributes to sperm capacitation and hyperactivation, causing a more violent and rapid non-linear motility pattern as the sperm approach the oocyte. the capacitated spermatozoon and the oocyte meet and interact in the "ampulla" of the fallopian tube. rheotaxis, thermotaixs and chemotaxis are known mechanisms in guiding sperm towards the egg during the final stage of sperm migration. spermatozoa respond (see sperm thermotaxis) to the temperature gradient of ~2 °c between the oviduct and the ampulla, and chemotactic gradients of progesterone have been confirmed as the signal emanating from the cumulus oophorus cells surrounding rabbit and human oocytes. capacitated and hyperactivated sperm respond to these gradients by changing their behaviour and moving towards the cumulus-oocyte complex. other chemotactic signals such as formyl met-leu-phe (fmlf) may also guide spermatozoa.
fertilisation
section::::fusion.









































after the sperm enters the cytoplasm of the oocyte (also called ovocyte), the tail and the outer coating of the sperm disintegrate and the cortical reaction takes place, preventing other sperm from fertilizing the same egg. the oocyte now undergoes its second meiotic division producing the haploid ovum and releasing a polar body. the sperm nucleus then fuses with the ovum, enabling fusion of their genetic material.









































section::::fusion.:cell membranes.









































the fusion of cell membranes of the secondary oocyte and sperm takes place.









































section::::fusion.:transformations.
human fertilization