Human Reproduction

The human reproduction cycle starts with the penetration of the penis into the vagina resulting in ejaculation of the spermatozoonatozoonatozoa. The spermatozoon then travels up the cervix perfect the uterus tract and into the ovary ducts with the help of chemotaxis quest a race of progesterone secreted by cells surrounding the tributary oocyte, where a secondary oocyte from a graffian follicle is awaiting fertilization. Fertilization begins with the binding of a sperm popular opinion to the glycoprotein coating of the unessential oocyte called the zone pellucida. Exocytosis of the acrosome at the tip of the sperm head releases enzymes that digest a path through the geographical zone and enable the sperm head to bind to the plasma membrane of the oocyte, as soon as this happens the secondary oocyte goes into meiosis peg down two. When the spermatozoa fuses with the zona pellicuda it disintergrates leaving only the heart and soul to infix the secondary oocyte, the secondary oocyte and the spermatozoa have 23 chromosomes each and when the heart and soul enters the secondary oocyte it is now a secondary oocyte with 46 chromosomes. currently the nucleus of the successful sperm enlarges into the male pronucleus. At the analogous time, secondary oocyte completes meiosis II forming a second opposite physical structure and the distaff pronucleus, it is now known as an egg cell.

The male and female pronuclei move toward each different while duplicating their DNA in S phase. Their nuclear envelopes disintegrate. A spindle is formed following replication of the sperms cent riole, and a sound launch of dyads assembl! es on it. The fertilized ovum now known as the fertilized ovum is now go down for its first mitosis. When this is done, 2 cells each with a diploid set of chromosomes are formed. cleavage now happens which is a series of rapid mitotic divisions that subdivides the cytoplasm of the zygote into smaller, essentially equipotential cells called blastomeres contained by the zona pellucida. Cleavage generates a cellular system essential for further...If you want to sign a plenteous essay, order it on our website: OrderCustomPaper.com

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