Human fertilization is the union of a human egg and sperm, usually occurring in the ampulla of the uterine tube. The result of this union is the production of a zygote cell, or fertilized egg, initiating prenatal development. Scientists discovered the dynamics of human fertilization in the nineteenth century.[1] The process of fertilization involves a sperm fusing with an ovum. The most common sequence begins with ejaculation during copulation, follows with ovulation, and finishes with fertilization. Various exceptions to this sequence are possible, including artificial insemination, In vitro fertilization, external ejaculation without copulation, or copulation shortly after ovulation.[2][3][4]Upon encountering the secondary oocyte, the acrosome of the sperm produces enzymes which allow it to burrow through the outer jelly coat of the egg. The sperm plasma then fuses with the egg's plasma membrane, the sperm head disconnects from its flagellum and the egg travels down the Fallopian tube to reach the uterus. Ovulation is the release of egg from the ovaries. In humans, this event occurs when the de Graaf's follicles rupture and release the secondary oocyte ovarian cells.[1] After ovulation, during the luteal phase, the egg will be available to be fertilized by sperm. In addition, the uterine lining (endometrium) is thickened to be able to receive a fertilized egg. If no conception occurs, the uterine lining as well as blood will be shed during menstruation.[2] Human reproduction is any form of sexual reproduction resulting in human fertilization, typically involving sexual intercourse between a man and a woman. During sexual intercourse

1. Human fertilization is the union of a human egg and sperm, usually occurring in the ampulla of the
uterine tube. The result of this union is the production of a zygote cell, or fertilized egg,
initiating prenatal development. Scientists discovered the dynamics of human fertilization in the
nineteenth century.[1]
The process of fertilization involves a sperm fusing with an ovum. The most common sequence
begins with ejaculation during copulation, follows with ovulation, and finishes with fertilization. Various
exceptions to this sequence are possible, including artificial insemination, In vitro fertilization, external
ejaculation without copulation, or copulation shortly after ovulation.[2][3][4]Upon encountering the
secondary oocyte, the acrosome of the sperm produces enzymes which allow it to burrow through the
outer jelly coat of the egg. The sperm plasma then fuses with the egg's plasma membrane, the sperm
head disconnects from its flagellum and the egg travels down the Fallopian tube to reach the uterus.
Ovulation is the release of egg from the ovaries. In humans, this event occurs when the de Graaf's
follicles rupture and release the secondary oocyte ovarian cells.[1] After ovulation, during the luteal
phase, the egg will be available to be fertilized by sperm. In addition, the uterine lining (endometrium)
is thickened to be able to receive a fertilized egg. If no conception occurs, the uterine lining as well as
blood will be shed during menstruation.[2]
Human reproduction is any form of sexual reproduction resulting in human fertilization, typically
involving sexual intercourse between a man and a woman. During sexual intercourse, the interaction
between the male and female reproductive systems results in fertilization of the woman's ovum by the
man's sperm. These are specialized reproductive cells called gametes, created in a process
called meiosis. While normal cells contains 46 chromosomes, 23 pairs, gamete cells only contain 23
chromosomes, and it is when these two cells merge into one zygote cell that genetic
recombination occurs and the new zygote contains 23 chromosomes from each parent, giving them
23 pairs. After a gestation period, typically for nine months, is followed by childbirth. The fertilization
of the ovum may be achieved by artificial insemination methods, which do not involve sexual
intercourse.
In humans (as in all other mammals, except for monotremes), implantation is the very early stage
of pregnancy at which the conceptus adheres to the wall of the uterus.[1] At this stage of prenatal
development, the conceptus is a blastocyst. It is by this adhesion that the foetus receives oxygen and
nutrients from the mother to be able to grow.
In humans, implantation of a fertilized ovum is most likely to occur about 9 days after ovulation,
ranging between 6 and 12 days.
Menstruation, also known as a period or monthly,[1] is the regular discharge of blood and mucosal
tissue from the inner lining of the uterus through the vagina.[2] Up to 80% of women report having
some symptoms prior to menstruation.[3]Common symptoms include acne, tender breasts, bloating,
feeling tired, irritability, and mood changes.[4] These symptoms interfere with normal life and therefore
qualify as premenstrual syndrome in 20 to 30% of women. In 3 to 8%, they are severe.