The human reproductive system usually involves internal fertilization by sexual intercourse. During this process, the male inserts his erect penis into the female's vagina and ejaculates semen, which contains sperm. A small portion of the sperm pass through the cervix into the uterus, and then into the fallopian tubes for fertilization of the ovum. Only one sperm is required to fertilize the ovum. Upon successful fertilization, the fertilized ovum, or zygote, travels out of the fallopian tube and into the uterus, where it implants in the uterine wall. This marks the beginning of gestation, better known as pregnancy, which continues for nine months as the foetus develops. When the foetus has developed to a certain point, pregnancy is concluded with childbirth or labor. During labor, the muscles of the uterus contract and the cervix dilates over the course of hours, and the baby passes out of the vagina. Human infants are nearly helpless and require high levels of parental care. Infants rely on their caregivers for comfort, cleanliness, and food. Food may be provided by breastfeeding or formula feeding.[1]
The female reproductive system has two functions: The first is to produce egg cells, and the second is to protect and nourish the fetus until birth. The male reproductive system has one function, and it is to produce and deposit sperm. Humans have a high level of sexual differentiation. In addition to differences in nearly every reproductive organ, numerous differences typically occur in secondary sexual characteristics [reproduction].
The male reproductive system is a series of organs located outside of the body and around the pelvis region of a male that contribute towards the reproduction process. The primary direct function of the male reproductive system is to provide the male sperm for fertilization of the ovum.
The major reproductive organs of the male can be grouped into three categories. The first category is sperm production and storage. Production takes place in the testes which are housed in the temperature regulating scrotum, immature sperm then travel to the epididymis for development and storage. The second category are the ejaculatory fluid producing glands which include the seminal vesicles, prostate, and the vas deferens. The final category are those used for copulation, and deposition of the spermatozoa (sperm) within the male, these include the penis, urethra, vas deferens, and Cowper's gland also called bulbo-urethral gland.
Major secondary sexual characteristics includes: larger, more muscular stature, deepened voice, facial and body hair, broad shoulders, and development of an adam's apple. An important sexual hormone of males is androgen, and particularly testosterone.
The testes release a hormone that controls the development of sperm. This hormone is also responsible for the development of physical characteristics in men such as facial hair and a deep voice.
The human female reproductive system is a series of organs primarily located inside of the body and around the pelvic region of a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vulva, which leads to the vagina, the vaginal opening, to the uterus; the uterus, which holds the developing fetus; and the ovaries, which produce the female's ova. The breasts are involved during the parenting stage of reproduction, but in most classifications they are not considered to be part of the female reproductive system.
The vagina meets the outside at the vulva, which also includes the labia, clitoris and urethra; during intercourse this area is lubricated by mucus secreted by the Bartholin's glands. The vagina is attached to the uterus through the cervix, while the uterus is attached to the ovaries via the fallopian tubes. Each ovary contains hundreds of egg cells or ova (singular ovum).
Approximately every 28 days, the pituitary gland releases a hormone that stimulates some of the ova to develop and grow. One ovum is released and it passes through the fallopian tube into the uterus. Hormones produced by the ovaries prepare the uterus to receive the ovum. The lining of the uterus, called the endometrium, and unfertilized ova are shed each cycle through the process of menstruation. If the ovum is fertilized by sperm, it attaches to the endometrium and the fetus develops.
The development of the reproductive system and the development of the urinary system are closely tied in the development of the human fetus. Despite the differences between the adult female and male are derived from the intermediate mesoderm. The three main fetal precursors of the reproductive organs are the Wolffian duct, Mllerian ducts, and the gonad. Endocrine hormones are a well known and critical controlling factor in the normal differentiation of the reproductive system.[2]
The Wolffian duct forms the epididymis, vas deferens, ductus deferens, ejaculatory duct, and seminal vesicle in the male reproductive system and essentially disappears in the female reproductive system. For the Mllerian Duct this process is reversed as it essentially disappears in the male reproductive system and forms the fallopian tubes, uterus, and vagina in the female system. In both sexes the gonad goes on to form the testes and ovaries, because they are derived from the same undeveloped structure they are considered homologous organs. There are a number of other homologous structures shared between male and female reproductive systems. However, despite the similarity in function of the female fallopian tubes and the male epididymis and vas deferens, they are not homologous but rather analogous structures as they arise from different fetal structures.
The production of gametes takes place within the gonads through a process known as gametogenesis. Gametogenesis occurs when certain types of germ cells undergo meiosis to split the normal diploid number of chromosome(n=46) into haploids cells containing only 23 chromosomes.[3]
In males, this process is known as spermatogenesis and takes place only after puberty in the seminiferous tubules of the testes. The immature spermatozoon or sperm are then sent to the epididymis where they gain a tail and motility. Each of the original diploid germs cells or primary spermatocytes forms four functional gametes which is each forever young. The production and survival of sperms require a temperature that is lower than the normal core body temperature. Since the scrotum, where the testes is present, is situated outside the body cavity, it provides a temperature about 3C below normal body temperature.
In females, gametogenesis is known as oogenesis which occurs in the ovarian follicles of the ovaries. This process does not produce mature ovum until puberty. In contrast with males, each of the original diploid germ cells or primary oocytes will form only one mature ovum, and three polar bodies which are not capable of fertilization It has long been understood that in females, unlike males, all of the primary oocytes ever found in a female will be created prior to birth, and that the final stages of ova production will then not resume until puberty.[3] However, recent scientific data has challenged that hypothesis.[4] This new data indicates that in at least some species of mammal oocytes continue to be replenished in females well after birth.[5]
Like all complex organ systems the human reproductive system is affected by many diseases. There are four main categories of reproductive diseases in humans. They are: 1) genetic or congenital abnormalities, 2) cancers, 3) infections which are often sexually transmitted diseases, and 4) functional problems cause by environmental factors, physical damage, psychological issues, autoimmune disorders, or other causes. The best known type of functional problems include sexual dysfunction and infertility which are both broad terms relating to many disorders with many causes. The human reproductive system usually involves internal fertilization by sexual intercourse. During this process, the male inserts his erect penis into the female's vagina and ejaculates semen, which contains sperm. The sperm then travels through the vagina and cervix into the uterus or fallopian tubes for fertilization of the ovum. Upon successful fertilization and implantation, gestation of the fetus then occurs within the female's uterus for approximately nine months, this process is known as pregnancy in humans. Gestation ends with birth, the process of birth is known as labor. Labor consists of the muscles of the uterus contracting, the cervix dilating, and the baby passing out the vagina (the female genital organ). Human's babies and children are nearly helpless and require high levels of parental care for many years. One important type of parental care is the use of the mammary glands in the female breasts to nurse the baby.[1]
Specific reproductive diseases are often symptoms of other diseases and disorders, or have multiple, or unknown causes making them difficult to classify. Examples of unclassifiable disorders include Peyronie's disease in males and endometriosis in females. Many congenital conditions cause reproductive abnormalities but are better known for their other symptoms, these include: Turner syndrome, Klinefelter's syndrome, Cystic fibrosis, and Bloom syndrome.[6]
View original post here:
Human reproductive system - Wikipedia
- World Health Organization reference values for human semen characteristics [Last Updated On: August 17th, 2024] [Originally Added On: April 6th, 2010]
- Economic consequences of overweight and obesity in infertility: a framework for evaluating the costs and outcomes of fertility care [Last Updated On: August 17th, 2024] [Originally Added On: April 6th, 2010]
- Maternal metabolism and obesity: modifiable determinants of pregnancy outcome [Last Updated On: August 17th, 2024] [Originally Added On: April 6th, 2010]
- Brain imaging studies of appetite in the context of obesity and the menstrual cycle [Last Updated On: August 17th, 2024] [Originally Added On: April 6th, 2010]
- The impact of body mass index on semen parameters and reproductive hormones in human males: a systematic review with meta-analysis [Last Updated On: August 17th, 2024] [Originally Added On: April 6th, 2010]
- Options for fertility preservation in prepubertal boys [Last Updated On: August 17th, 2024] [Originally Added On: April 6th, 2010]
- Xenografting of testicular tissue from an infant human donor results in accelerated testicular maturation [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Karyotype of miscarriages in relation to maternal weight [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Endoglandular trophoblast, an alternative route of trophoblast invasion? Analysis with novel confrontation co-culture models [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Regulation of extravillous trophoblast invasion by uterine natural killer cells is dependent on gestational age [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Functional regulation of thymic stromal lymphopoietin on proliferation and invasion of trophoblasts in human first-trimester pregnancy [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Home self-administration of vaginal misoprostol for medical abortion at 50-63 days compared with gestation of below 50 days [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Prospective study of the forearm bone mineral density of long-term users of the levonorgestrel-releasing intrauterine system [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Functional attenuation of human sperm by novel, non-surfactant spermicides: precise targeting of membrane physiology without affecting structure [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Characteristics indicating adenomyosis coexisting with leiomyomas: a case-control study [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- The risk of post-molar gestational trophoblastic neoplasia is higher in heterozygous than in homozygous complete hydatidiform moles [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Cumulative ongoing pregnancy rate achieved with oocyte vitrification and cleavage stage transfer without embryo selection in a standard infertility program [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Pregnancy outcome in female childhood cancer survivors [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Offering excess oocyte aspiration and vitrification to patients undergoing stimulated artificial insemination cycles can reduce the multiple pregnancy risk and accumulate oocytes for later use [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Avoidance of weekend oocyte retrievals during GnRH antagonist treatment by simple advancement or delay of hCG administration does not adversely affect IVF live birth outcomes [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Who should pay for assisted reproductive techniques? Answers from patients, professionals and the general public in Germany [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Sperm donor limits that control for the 'relative' risk associated with the use of open-identity donors [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Long-term cryostorage of sperm in a human sperm bank does not damage progressive motility concentration [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Screening for biomarkers of spermatogonia within the human testis: a whole genome approach [Last Updated On: August 17th, 2024] [Originally Added On: April 14th, 2010]
- Avoiding transgenerational risks of mitochondrial DNA disorders: a morally acceptable reason for sex selection? [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Cross border reproductive care in six European countries [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Morphometric dimensions of the human sperm head depend on the staining method used [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- ESX1 gene expression as a robust marker of residual spermatogenesis in azoospermic men [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Innovative virtual reality measurements for embryonic growth and development [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Consecutive or non-consecutive recurrent miscarriage: is there any difference in carrier status? [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- A longitudinal study of contraception and pregnancies in the same women followed for a quarter of a century [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Predictors of bleeding and user satisfaction during consecutive use of the levonorgestrel-releasing intrauterine system [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Direct proportional relationship between endometrioma size and ovarian parenchyma inadvertently removed during cystectomy, and its implication on the management of enlarged endometriomas [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Large prospective, pregnancy and infant follow-up trial assures the health of 1000 fetuses conceived after treatment with the GnRH antagonist ganirelix during controlled ovarian stimulation [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Altered aquaporin expression in women with polycystic ovary syndrome: hyperandrogenism in follicular fluid inhibits aquaporin-9 in granulosa cells through the phosphatidylinositol 3-kinase pathway [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Fast-release orodispersible tramadol as analgesia in hysterosalpingography with a metal cannula or a balloon catheter [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Xenotransplantation of cryopreserved human ovarian tissue into murine back muscle [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Predictors of psychological distress in patients starting IVF treatment: infertility-specific versus general psychological characteristics [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Psychological adjustment, knowledge and unmet information needs in women undergoing PGD [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Mothers of IVF and spontaneously conceived twins: a comparison of prenatal maternal expectations, coping resources and maternal stress [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Psychological well-being and sexarche in women with polycystic ovary syndrome [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Is human fecundity declining in Western countries? [Last Updated On: August 17th, 2024] [Originally Added On: May 20th, 2010]
- Impaired glucose tolerance, type 2 diabetes and metabolic syndrome in polycystic ovary syndrome: a systematic review and meta-analysis [Last Updated On: August 17th, 2024] [Originally Added On: June 5th, 2010]
- Current achievements and future research directions in ovarian tissue culture, in vitro follicle development and transplantation: implications for fertility preservation [Last Updated On: August 17th, 2024] [Originally Added On: June 5th, 2010]
- Human studies on genetics of the age at natural menopause: a systematic review [Last Updated On: August 17th, 2024] [Originally Added On: June 5th, 2010]
- Beyond oxygen: complex regulation and activity of hypoxia inducible factors in pregnancy [Last Updated On: August 17th, 2024] [Originally Added On: June 5th, 2010]
- Current knowledge of the aetiology of human tubal ectopic pregnancy [Last Updated On: August 17th, 2024] [Originally Added On: June 5th, 2010]
- Economic contraction and birth outcomes: an integrative review [Last Updated On: August 17th, 2024] [Originally Added On: June 5th, 2010]
- Teratogenic mechanisms of medical drugs [Last Updated On: August 17th, 2024] [Originally Added On: June 5th, 2010]
- Levels of semenogelin in human spermatozoa decrease during capacitation: involvement of reactive oxygen species and zinc [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Apoptosis and meiotic segregation in ejaculated sperm from Robertsonian translocation carrier patients [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- In humans, zona pellucida glycoprotein-1 binds to spermatozoa and induces acrosomal exocytosis [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Variants of the EPPIN gene affect the risk of idiopathic male infertility in the Han-Chinese population [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Epidermal clitoral inclusion cysts: not a rare complication of female genital mutilation [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- PCOSMIC: a multi-centre randomized trial in women with PolyCystic Ovary Syndrome evaluating Metformin for Infertility with Clomiphene [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Single versus double intrauterine insemination in multi-follicular ovarian hyperstimulation cycles: a randomized trial [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Soluble HLA-G is an independent factor for the prediction of pregnancy outcome after ART: a German multi-centre study [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Obstetric outcomes after transfer of vitrified blastocysts [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Occasional involvement of the ovary in Ewing sarcoma [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Y chromosome microdeletions, sperm DNA fragmentation and sperm oxidative stress as causes of recurrent spontaneous abortion of unknown etiology [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Development and preliminary validation of the fertility status awareness tool: FertiSTAT [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Xenotransplantation of human ovarian tissue to nude mice: comparison between four grafting sites [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Involvement of CFTR in oviductal HCO3- secretion and its effect on soluble adenylate cyclase-dependent early embryo development [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Effect of endometriosis on the protein expression pattern of follicular fluid from patients submitted to controlled ovarian hyperstimulation for in vitro fertilization [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Activin A regulates trophoblast cell adhesive properties: implications for implantation failure in women with endometriosis-associated infertility [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Clinical significance of sperm DNA damage in assisted reproduction outcome [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Fall in implantation rates following ICSI with sperm with high DNA fragmentation [Last Updated On: August 17th, 2024] [Originally Added On: June 17th, 2010]
- Prevalence of unsuspected uterine cavity abnormalities diagnosed by office hysteroscopy prior to in vitro fertilization [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]
- Ultra-conservative fertility-sparing strategy for bilateral borderline ovarian tumours: an 11-year follow-up [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]
- Fertility after autologous ovine uterine-tubal-ovarian transplantation by vascular anastomosis to the external iliac vessels [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]
- Uterus transplantation in the baboon: methodology and long-term function after auto-transplantation [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]
- Prestimulation parameters predicting live birth in anovulatory WHO Group II patients undergoing ovulation induction with gonadotrophins [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]
- Transfer of a selected single blastocyst optimizes the chance of a healthy term baby: a retrospective population based study in Australia 2004-2007 [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]
- Disclosure patterns of mode of conception among mothers and fathers-5-year follow-up of the Copenhagen Multi-centre Psychosocial Infertility (COMPI) cohort [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]
- Assisted reproductive technology in Europe, 2006: results generated from European registers by ESHRE [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]
- A decade of sperm washing: clinical correlates of successful insemination outcome [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]
- Sperm DNA integrity in cancer patients before and after cytotoxic treatment [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]
- Speriolin is a novel human and mouse sperm centrosome protein [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]
- No influence of body mass index on first trimester fetal growth [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]
- HLA sharing among couples appears unrelated to idiopathic recurrent fetal loss in Saudi Arabia [Last Updated On: August 17th, 2024] [Originally Added On: July 21st, 2010]