Reproductive system 26303 220217030 2008-06-18T20:30:53Z JAnDbot 1725149 robot Removing: fr, it, pl, uk Modifying: es [[Image:Scheme female reproductive system-en.svg|thumb|right|A pictorial illustration of the human female reproductive system.]] [[Image:Penis.svg|thumb|right|A pictorial illustration of the human male reproductive system.]] {{otheruses4|sexual reproductive systems|the reproductive systems of asexual organisms|Asexual reproduction}} The '''reproductive system''' is a system of [[Organ (anatomy)|organs]] within an [[organism]] which work together for the purpose of [[reproduction]]. Many non-living substances such as fluids, [[hormone]]s, and [[pheromone]]s are also important accessories to the reproductive system.<ref>[http://training.seer.cancer.gov/module_anatomy/unit12_1_repdt_intro.html Introduction to the Reproductive System.] SEER's Training Website. U.S. National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Program.</ref> Unlike most organ systems, the [[sex]]es of [[sexual differentiation|differentiated]] [[species]] often have significant differences. These differences allow for a combination of genetic material between two individuals, which allows for the possibility of greater [[genes|genetic]] [[Fitness (biology)|fitness]] of the [[offspring]].<ref name=Adam>[http://www.besthealth.com/besthealth/bodyguide/reftext/html/repr_sys_fin.html Reproductive System 2001] Body Guide powered by Adam</ref> The major organs of the human reproductive system include the external [[genitalia]] (penis and vulva) as well as a number of internal organs including the [[gamete]] producing [[gonad]]s (testicles and ovaries). Diseases of the human reproductive system are very common and widespread, particularly [[Infectious disease|communicable]] [[sexually transmitted disease]]s.<ref>[http://www.cdcnpin.org/scripts/std/std.asp#2 STD's Today] National Prevention Network, Center for Disease Control, United States Government, retrieving 2007</ref> Most other [[vertebrate]] animals have generally similar reproductive systems consisting of gonads, ducts, and openings. However, there is a great diversity of physical [[adaptation]]s as well as [[Reproduction|reproductive strategies]] in every group of vertebrates. == Human reproductive system == {{See|Human reproduction}} [[Human reproduction]] takes place as [[internal fertilization]] by [[sexual intercourse]]. During this process, the [[erect]] [[penis]] of the [[male]] is inserted into the [[female|female's]] [[vagina]] until the male [[ejaculate]]s [[semen]], which contains [[sperm]], into the female's vagina. The sperm then travels through the vagina and cervix into the [[uterus]] or [[fallopian tube]]s for fertilization of the [[ovum]]. Upon successful [[human fertilization|fertilization]] and implantation, [[gestation]] of the [[foetus]] 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 in known as labor. Labor consists of the [[muscle]]s of the uterus contracting, the cervix [[dilate|dilating]], and the baby passing out the vagina. 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 gland]]s in the female [[breast]]s to [[lactation|nurse]] the baby.<ref>[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/Sexual_Reproduction.html Sexual Reproduction in Humans.] 2006. John W. Kimball. Kimball's Biology Pages, and online textbook.</ref> Humans have a high level of [[sexual differentiation]]. In addition to differences in nearly every reproductive organ, numerous differences typically occur in [[secondary sexual characteristic]]s and in sexual and parental behaviours. ===Male reproductive system=== {{main|Male reproductive system (human)}} [[Image:Male genitalia reworked.jpg|thumb|left|Partially shaved erect male genitalia. 1. [[Testicles]], 2. [[Epididymis]], 3. [[Corpus cavernosa]], 4. [[Foreskin]], 5. [[Frenulum of prepuce of penis|Frenulum]], 6. [[urethra|Urethral opening]] , 7. [[Glans penis]], 8. [[Corpus spongiosum]], 9. [[Penis]], 10. [[Scrotum]].]] The human male reproductive system is a series of organs located outside of the body and around the [[pelvis|pelvic]] region of a [[male]] that contribute towards the [[Reproduction|reproductive]] process. The primary direct function of the male reproductive system is to provide the male [[gamete]] or [[spermatozoa]] 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 female, these include the [[penis]], [[urethra]], [[vas deferens]], and [[Cowper's gland]]. Major secondary sexual characteristics include: larger, more muscular stature, deepened voice, [[facial hair|facial]] and [[body hair]], broad shoulders, and development of an [[adam's apple]]. An important sexual hormone of males is [[androgen]], and particularly [[testosterone]].<ref name="kimball">[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/SexHormones.html Hormones of the Reproductive System] 2006. John W. Kimball. Kimball's Biology Pages, and online textbook.</ref> ===Female reproductive system=== {{main|Female reproductive system (human)}} [[Image:Flushvul numbered.jpg|thumb|right|Photograph of the [[vulva]]. 1. [[Pubic hair]] (shaved), 2.[[Clitoral hood]], 3. [[Clitoris]], 4. [[Labia majora]], 5. [[Labia minora]] (enclosing the [[Vagina|Vaginal Opening]]), 6. [[Perineum]].]] The human female reproductive system is a series of organs primarily located inside of the body and around the [[pelvis|pelvic]] region of a [[female]] that contribute towards the [[Reproduction|reproductive]] process. The human female reproductive system contains three main parts: the [[vagina]], which acts as the receptacle for the male's sperm, the [[uterus]], which holds the developing fetus, and the [[Ovary|ovaries]], which produce the female's ova. The breasts are also an important reproductive organ during the parenting stage of reproduction. The vagina meets the outside at the [[vulva]], which also includes the [[labia (genitalia)|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]]. At certain intervals, typically approximately every 28 [[day]]s, the ovaries release an [[ovum]], which passes through the fallopian tube into the uterus. The lining of the uterus, called the [[endometrium]], and unfertilized ova are shed each cycle through a process known as [[menstruation]]. Major secondary sexual characteristics include: a smaller stature, a high percentage of [[body fat]], wider [[hip]]s, development of mammary glands, and enlargement of breasts. Important sexual hormones of females include [[estrogen]] and [[progesterone]].<ref name="kimball" /> === Production of gametes=== {{main|Spermatogenesis|Oogenesis}} The production of gametes takes place within the gonads through a process known as [[gametogenesis]]. Gametogenesis occurs when certain types of [[germ cell]]s undergo [[meiosis]] to split the normal diploid number of [[chromosome]]s in humans (n=46) into haploids cells containing only 23 chromosomes.<ref name=sexcell>[http://www.besthealth.com/besthealth/bodyguide/reftext/html/repr_sys_fin.html#development Development of sex cells] in Reproductive system, Body Guide. Adam.</ref> 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 [[spermatocyte]]s forms four functional gametes which is each capable of fertilization. In females gametogenesis is known as [[oogenesis]] and unlike males, all of the primary [[oocyte]]s ever found in a female will be created in the [[ovarian follicle]]s of the ovaries prior to [[birth]]. The final stages of ova production will then not resume until puberty.<ref name=sexcell /> In females, each of the original diploid germ cells or primary [[oocyte]]s will form only one mature ovum, and three [[polar body|polar bodies]] which are not capable of fertilization. ===Development of the reproductive system=== {{main|Development of the urinary and reproductive organs}} The development of the reproductive system and [[urinary system]]s are closely tied in the [[prenatal development|development]] of the human fetus. Despite the differences between the [[adult]] male and female reproductive system, there are a number of [[Homology (biology)|homologous]] structures shared between them due to their common origins within the fetus. Both organ systems are derived from the [[intermediate mesoderm]]. The three main fetal precursors of the reproductive organs are the [[Wolffian duct]], [[Müllerian ducts]], and the [[gonad]]. [[endocrine system|Endocrine]] hormones are a well known and critical controlling factor in the normal differentiation of the reproductive system.<ref>[http://www.epa.gov/endocrine/inventory/RTD-KELC.html EDRI Federal Project Inventory: Cellular and Molecular Mechanisms of Abnormal Reproductive Development] US EPA. Dr. William R. Kelce. 2006.</ref> The Wolffian duct forms the epididymis, vas deferns, ductus deferens, [[ejaculatory duct]], and seminal vesicle in the male reproductive system and essentially disappears in the female reproductive system. For the Müllerian 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 [[Homology (biology)|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 [[analogy (biology)|analogous]] structures as they arise from different fetal structures. {| class="wikitable" |+'''Examples of [[List of homologues of the human reproductive system|homologous human reproductive organs]]''' ! Male organ ! Female organ ! Shared function |- | [[Cowper's gland]] | [[Bartholin's gland]]s | Lubrication secretions. |- | [[Penis]] | [[Clitoris]] | Erectile tissue and sensation |- | [[Testes]] | [[Ovary]] | Gamete production |- | [[Prostate gland]] | [[Skene's gland]] | Ejaculatory fluid and sensation. |} ===Diseases of the human reproductive system=== {{main|Reproductive system disease}} Like all complex organ systems the human reproductive system is affected by many diseases. There are four main categories of reproductive [[disease]]s in humans. They are: 1) genetic or [[congenital abnormalities]], 2) [[cancer]]s, 3) [[infection]]s which are often [[sexually transmitted disease]]s, and 4) functional problems cause by [[environmental factor]]s, physical damage, psychological issues, [[autoimmune disorder]]s, 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. Specific reproductive diseases are often [[symptom]]s of other diseases and [[disease|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 congenial conditions cause reproductive abnormalities but are better known for their other symptoms, these include: [[Turner syndrome]], [[Klinefelter syndrome]], [[Cystic fibrosis]], and [[Bloom syndrome]].<ref>[http://ghr.nlm.nih.gov/ghr/conditionsByCategory/show/reproductivesystem Genetic Conditions > Reproductive system.] 2007. Genetics Home Reference. U.S. National Library of Medicine.</ref> It is also known that [[Endocrine disruptor|disruption of the endocrine system]] by certain chemical adversely affects the development of the [[reproductive system]] and can cause vaginal [[cancer]].<ref name="NIEHS">{{cite web |url= http://www.niehs.nih.gov/health/topics/agents/endocrine/docs/endocrine.pdf |title= Endocrine Disruptors |accessdate=2007-11-29 |date= 2006 |format= PDF |publisher= National Institute of Environmental Health Sciences}}</ref> Many other reproductive diseases have also been link to exposure to synthetic and environmental chemicals. Common chemicals with known links to reproductive disorders include: [[lead]], [[dioxin]], [[styrene]], [[toluene]], and [[pesticide]]s.<ref>[http://www.protectingourhealth.org/newscience/infertility/2003-04peerreviewinfertility.htm Infertility and Related Reproductive Disorders.] 2003. Ted Schettler, MD. The collaborative on health and the environment.</ref> ====Examples of congenial abnormalities==== *[[Kallmann syndrome]] - Genetic disorder causing decreased functioning of the sex hormone-producing glands caused by a deficiency of a hormone. *[[Cryptorchidism]] - Absence of one or both testes from the scrotum. *[[Androgen insensitivity syndrome]] - A genetic disorder causing people who are genetically male (i.e. XY chromosome pair) to develop sexually as a female due to an inability to utilize androgen. *[[Intersexuality]] - A person who has genitalia or/and other sexual traits which are not clearly male or female. ====Examples of cancers==== *[[Prostate cancer]] - Cancer of the prostate gland. *[[Breast cancer]] - Cancer of the mammary gland. *[[Ovarian cancer]] - Cancer of the ovary. *[[Penile cancer]] - Cancer of penis. *[[Uterine sarcoma|Uterine cancer]] - Cancer of the uterus. ====Examples of infections==== *[[HIV]] - Infection by the [[retrovirus]] known as human immunodeficiency virus. *[[Genital warts]] - Sexually transmitted infection caused by some sub-types of [[human papillomavirus]] (HPV). *[[Herpes simplex]] - Sexually transmitted infection caused by a virus called herpes simplex virus (HSV) type 2 *[[Gonorrhea]] - Common sexually transmitted disease caused by the Gram-negative bacterium ''Neisseria gonorrheae'' *[[Yeast infection]] - Infection of the vagina by any species of the fungus genus ''[[candida (genus)|Candida]]''. *[[Pelvic inflammatory disease]] - Painful infection of the female uterus, fallopian tubes, and/or ovaries with associated scar formation and adhesions to nearby tissues and organs. *[[Syphilis]] - Sexually transmitted infection caused by the bacterium ''[[Treponema pallidum]]''. *[[Pubic lice]] - Infection of the [[pubic hair]] by crab lice, ''Phthirius pubis''. *[[Trichomoniasis]] - Sexually transmitted infection by the single-celled [[protozoa]]n [[parasite]] ''Trichomonas vaginalis''. ====Examples of functional problems==== *[[Impotence]] - The inability of a male to produce or maintain an erection. *[[Hypogonadism]] - A lack of function of the gonads, in regards to either hormones or gamete production. *[[Ectopic pregnancy]] - When a fertilized ovum is implanted in any tissue other than the uterine wall. *[[Inhibited sexual desire]] - A low level of sexual desire and interest. *[[Female sexual arousal disorder]] - A condition of decreased, insufficient, or absent lubrication in females during sexual activity *[[Premature ejaculation]] - A lack of voluntary control over ejaculation. ==Other vertebrates== {{seealso|Sexual reproduction}} [[Vertebrate]] [[animal]]s all share key elements of their reproductive systems. They all have gamete producing organs or [[gonad]]s. These gonads are then connected by [[oviduct]]s to an opening to the outside of the body, typically the cloaca, but sometime to a unique pore such as a vagina or [[intromittent organ]]. === Mammals === [[Image:Joey in pouch.jpg|thumb|Newborn [[Joey (marsupial)|joey]] sucking on a [[teat]] in the [[Pouch (marsupial)|pouch]]]] Most [[mammal]] reproductive systems are similar, however, there are some notable differences between the "normal" mammal and humans. For instance, most mammalian males have a penis which is stored internally until erect, and most have a penis bone or [[baculum]]. Additionally, males of most species do not remain continually sexually fertile as humans do. Like humans, most groups of mammals have descended testicles found within a scrotum, however, others have descended testicles that rest on the ventral body wall, and a few groups of mammals, such as elephants, have undescended testicles found deep within their body cavities near their [[kidney]]s.<ref>L. Werdelina, and A. Nilsonne 1999. The Evolution of the Scrotum and Testicular Descent in Mammals: a Phylogenetic View. Journal of Theoretical Biology Volume 196, Issue 1</ref><ref>[http://pharyngula.org/index/weblog/comments/descent_of_the_testicle/ Descent of the testicles.] P.Z. Myers. Pharyngula blog. 2004.</ref> [[Marsupial]]s are unique in that the female has two vaginae, both of which open externally through one orifice but lead to different compartments within the uterus; males usually have a two-pronged penis which corresponds to the females' two vaginae. Marsupials typically develop their offspring in an external [[Pouch (marsupial)|pouch]] containing [[teat]]s to which their newborn young ([[Joey (marsupial)|joey]]s) attach themselves for post uterine development. Also, marsupials have a unique prepenial scrotum.<ref>[http://books.google.com/books?id=HpjovN0vXW4C&pg=PA129&lpg=PA129&dq=marsupial+scrotum&source=web&ots=9mQ7K3OvQC&sig=pz9pr4gKpbeJ4eSRjHjejwF_Sdo Reproductive Physiology of Marsupials.] Hugh Tyndale-Biscoe, Marilyn B. Renfree. Published 1987, Cambridge University Press. ISBN 1397805218</ref> The uterus and vagina are unique to mammals with no homologue in birds, reptiles, amphibians, or fish.<ref name= pharangula>[http://pharyngula.org/index/weblog/comments/evolution_of_the_mammalian_vagina/P75/ Evolution of the mammalian vagina.] P.Z. Myers. Pharyngula blog. Tuesday, November 01, 2005.</ref> In place of the uterus the other [[vertebrate]] groups have an unmodified oviduct leading directly to a [[cloaca]], which is a shared exit-hole for gametes, [[urine]], and [[feces]]. Monotremes (i.e. [[platypus]] and [[echidna]]s), a group of egg-laying mammals, also lack a uterus and vagina, and in that respect have a reproductive system resembling that of a reptile. ===Birds=== Male and female birds have a [[cloaca]], an opening through which eggs, sperm, and wastes pass. Intercourse is performed by pressing the lips of the cloacae together, which is sometimes known as the "cloacal kiss", during which time the male transfers his sperm to the female. A few species of birds (e.g. most [[waterfowl]]) have a [[intromittent organ]] which is known as a phallus that is [[analogous]] to the mammals' penis. The female lays [[amniote|amniotic]] eggs in which the young gestate. Unlike most vertebrates female birds typically have only one functional ovary and [[oviduct]].<ref>[http://people.eku.edu/ritchisong/avianreproduction.html Avian Reproduction: Anatomy & the Bird Egg] Gary Ritchison. BIO 554/754 Ornithology. Eastern Kentucky University.</ref> As a group, birds, like mammals, are noted for their high level of parental care. === Reptiles === [[Reptiles]] are almost all [[sexual dimorphism|sexually dimorphic]], and exhibit internal fertilization through the cloaca. Some reptiles lay [[egg (biology)|egg]]s while others are viviparous (animals that deliver live young). Reproductive organs are found within the cloaca of reptiles. Most male reptiles have copulatory organs, which are usually retracted or inverted and stored inside the body. In turtles and crocodilians, the male has a single median penis-like organ, while male snakes and lizards each possess a pair of penis-like organs. [[Image:Frog in frogspawn.jpg|thumb|right|A female [[frog]] sitting in a mass of its own [[Spawn (biology)|spawn]].]] === Amphibians === Most [[amphibian]]s exhibit external fertilization of eggs, typically within the water, though some amphibians such as [[caecilian]]s have internal fertilization.<ref>{{cite book |last=Grzimek |first=B. |year=1974 |title=Grzimek's Animal Life Encyclopedia: Volume 5 Fishes II & Amphibians. |location=New York |publisher=Van Nostrand Reihnhold Co. |asin=B000HHFY52|pages=p. 301-302}}</ref> All have paired, internal gonads, connected by ducts to the cloaca. === Fish === {{main|Fish#Reproductive_method}} [[Fish]] exhibit a wide range of different reproductive strategies. Most fish however are [[oviparous]] and exhibit external fertilization. In this process, females use their cloaca to release a large quantities their gametes, called [[Spawn (biology)|spawn]], into the water and one or more males release "milt", a white fluid containing many sperm over the unfertilized eggs. Other species of fish are oviparous and have internal fertilization aided by pelvic or anal [[fin]]s that are modified into an [[intromittent organ]] analogous to the human penis.<ref>[http://www.lookd.com/fish/reproduction.html Fish Reproduction]</ref> A small portion of fish species are either viviparous or [[ovoviviparous]], and are collectively known as [[livebearer]]s.<ref>[http://www.advancedaquarist.com/issues/june2002/breeder.htm Science, Biology, and Terminology of Fish reproduction: Reproductive modes and strategies-part 1]. 2002. MARTIN MOE. THE BREEDER'S NET Online Magazine</ref> Fish gonads are typically pairs of either ovaries or testes. Most fish are sexually dimorphic but some species are [[hermaphrodite|hermaphroditic]] or [[unisexual]].<ref>[http://www.buschgardens.org/infobooks/BonyFish/reproduction.html Bony Fish Reproduction] 2002. SeaWorld/Busch Gardens Animal Information Database.</ref> ==Invertebrates== [[Invertebrate]]s have an extremely diverse array of reproductive systems, the only commonality may be that they all lay eggs. Also, aside from [[cephalopod]]s, and [[arthropod]]s, nearly all other invertebrates are [[hermaphroditic]] and exhibit [[external fertilization]]. ===Cephalopods=== All [[cephalopod]]s are [[sexual dimorphism|sexually dimorphic]] and reproduce by laying [[egg (biology)|egg]]s. Most cephalopods have semi-internal fertilization in which the male places his gametes inside the female's mantle cavity or [[pallial cavity]] to fertilize the [[Ovum|ova]] found in the female's single [[ovary]].<ref>[http://www.weichtiere.at/Mollusks/Kopffuesser/haupt.html Cephalopods.] The Living World of Molluscs. Robert Nordsieck.</ref> Likewise, male cephalopods have only a single [[teste]]. In the female of most cephalopods the [[nidamental gland]]s aid in development of the egg. The "penis" in most unshelled male cephalopods ([[Coleoidea]]) is a long and muscular end of the gonoduct used to transfer spermatophores to a modified arm called a [[hectocotylus]]. That in turn is used to transfer the spermatophores to the female. In species where the hectocotylus is missing, the "penis" is long and able to extend beyond the mantle cavity and transfers the spermatophores directly to the female. Many cephalopods shed their [[gonad]]s during reproduction, and thus only reproduce once. Most cephalopods die after reproducing. Females [[nautilus]] however, have the ability to regenerate their [[gonad]]s, making them the only cephalopods to spawn once per year. The females in many cephalopod species exhibit some level of parental protection for their eggs. ==See also== *[[Human anatomy|Major systems of the human body]] *[[Reproductive system disease]] *[[Sexual reproduction]] *[[Human sexuality]] *[[Human sexual behavior]] *[[Sex organ]] *[[Plant sexuality]] ==References== {{Reflist}} {{organ systems}} {{Female reproductive system}} {{Male reproductive system}} {{Development of urinary and reproductive systems}} [[Category:Reproductive system| ]] [[ar:جهاز تناسلي]] [[zh-min-nan:Seⁿ-thoàⁿ hē-thóng]] [[bs:Reproduktivni sistem]] [[ca:Sistema reproductor]] [[es:Aparato genital]] [[eo:Reprodukta sistemo]] [[hr:Spolni sustav]] [[id:Sistem reproduksi]] [[is:Æxlunarfæri]] [[he:מערכת הרבייה]] [[pt:Aparelho reprodutor]] [[ru:Репродуктивная система]] [[simple:Reproductive system]] [[sr:Репродуктивни систем]] [[sv:Fortplantningssystemet]] [[tl:Sistemang reproduktibo]] [[zh:生殖系统]]