Human Reproduction


Human reproduction is any form of sexual reproduction resulting in the conception of a child, typically involving sexual intercourse between a man and a woman. During sexual intercourse, the interaction between the male reproductive system and the female reproductive system results in fertilization of the woman's ovum by the man's sperm, which after a gestation period is followed by childbirth. The fertilization of the ovum may nowadays be achieved by artificial insemination methods, which do not involve sexual intercourse.


"WOMAN REPRODUCTIVE SYSTEM"

The female reproductive system likewise contains two main divisions: the vagina and uterus, which act as the receptacle for the semen, and the ovaries, which produce the female's ova. The vagina is attached to the uterus through the cervix, while the uterus is attached to the ovaries via the Fallopian tubes. At certain intervals, the ovaries release an ovum, which passes through the fallopian tube into the uterus.
If, in this transit, it meets with Spermatozoon, the sperm penetrate and merge with the egg, fertilizing it. The fertilization usually occurs in the oviducts, but can happen in the uterus itself. The zygote then implants itself in the wall of the uterus, where it begins the processes of embryogenesis and morphogenesis. When developed enough to survive outside the womb, the cervix dilates and contractions of the uterus propel the foetus through the birth canal, which is the vagina.
The ova, which are the female sex cells, are much larger than the spermatozoon and are normally formed with in the ovaries of the fetus before its birth. They are mostly fixed in location with in the ovary until their transit to the uterus, and contain nutrients for the later zygote and embryo. Over a regular interval, in response to hormonal signals, a process of oogenesis matures one ovum which is released and sent down the Fallopian tube. If not fertilized, this egg is flushed out of the system through menstruation.

"MALE REPRODUCTIVE SYSTEM"

The male reproductive is made up of a pp system contains two main divisions: the penis, and the testes, the latter of which is where sperm are produced. In humans, both of these organs are outside the abdominal cavity. Having the testes outside the abdomen best facilitates temperature regulation of the sperm, which require specific temperatures to survive.
Sperm are smaller than the female ovum, and live approximately 2 weeks after production, requiring males to produce them continuously from the time of sexual maturity until death.
A sperm cell is motile and swims via chemotaxis, using its flagellum to propel itself towards the ovum.

"FERTILIZATION"

The term conception commonly refers to fertilisation, which many people contend is "the point at which human life begins" -- as the successful fusion of gametes form a new organism. 'Conception' is usually defined as implantation and is thus a subject of semantic arguments about the beginning of pregnancy, within the abortion debate. Gastrulation, which occurs around 16 days after fertilisation, is the point in development when the implanted blastocyst develops three germ layers, the endoderm, the ectoderm and the mesoderm. It is at this point that the genetic code of the father becomes fully involved in the development of the embryo. Until this point in development, twinning is possible. Additionally, interspecies hybrids survive only until gastrulation, and have no chance of development afterward. However this stance is not entirely accepted as some human developmental biology literature refers to the "conceptus" and such medical literature refers to the "products of conception" as the post-implantation embryo and its surrounding membranes.[7] The term "conception" is not usually used in scientific literature because of its variable definition and connotation.