Reproductive system

Source: Wikipedia, the free encyclopedia.
This article is about the reproductive system of all types of organisms, including humans. For information specific to humans, see Human reproductive system.
Reproductive system
Details
Identifiers
Latinsystemata genitalia
TA98A09.0.00.000
TA23467
Anatomical terminology

The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical

genetic fitness of the offspring.[2]

Animals

See also: Sexual reproduction § Animals
Further information: Sex organ § Animals

In mammals, the major organs of the reproductive system include the external

communicable sexually transmitted infections.[3]

Most other vertebrates have similar reproductive systems consisting of gonads, ducts, and openings. However, there is a great diversity of physical adaptations as well as reproductive strategies in every group of vertebrates.

Vertebrates

Vertebrates share key elements of their reproductive systems. They all have gamete-producing organs known as gonads. In females, these gonads are then connected by oviducts to an opening to the outside of the body, typically the cloaca, but sometimes to a unique pore such as a vagina.

Humans

Main article: Human reproductive system

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 childbirth, delivery following 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.[4]

The female reproductive system has two functions: The first is to produce egg cells, and the second is to protect and nourish the offspring until birth. The male reproductive system has one function, and it is to produce and deposit sperm. Humans have a high level of

secondary sexual characteristics
.

Male
Main article: Male reproductive system

The male reproductive system is a series of organs located outside of the body and around the pelvic 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

Cowper's gland
.

Major secondary sex characteristics include 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.

Female
Main article: Female reproductive system

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

ovum
).

Approximately

fallopian tubes and awaits the sperm for fertilization to occur. When this does not occur, i.e. no sperm for fertilization, 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 will attach to the endometrium and embryonic development will begin.

Other mammals

Main article:
Mammalian reproductive system
suckles from a teat found within its mother's pouch
Didactic model of a mammal urogenital system.

Most

mammaries like human females do either. 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 kidneys.[6]

The

joeys) attach themselves for post uterine development. Also, marsupials have a unique prepenial scrotum.[9]
The 15 mm (5⁄8 in) long newborn joey instinctively crawls and wriggles the 15 cm (6 in), while clinging to fur, on the way to its mother's pouch.

In regards to males, the mammalian penis has a similar structure in reptiles and a small percentage of birds while the scrotum is only present in mammals. Regarding females, the vulva is unique to mammals with no homologue in birds, reptiles, amphibians, or fish.[10][11][12] The clitoris, however, can be found in reptiles and ratites.[13] In place of the uterus and vagina, non-mammal 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 echidnas), a group of egg-laying mammals, also lack a uterus, vagina, and vulva, and in that respect have a reproductive system resembling that of a reptile.

Dogs
Main article: Canine reproduction

In domestic canines, sexual maturity (puberty) occurs between the ages of 6 and 12 months for both males and females, although this can be delayed until up to two years of age for some large breeds.

Horses
Main article: Equine anatomy § Reproductive system

The mare's reproductive system is responsible for controlling gestation, birth, and lactation, as well as her estrous cycle and mating behavior. The stallion's reproductive system is responsible for his sexual behavior and secondary sex characteristics (such as a large crest).

Even-toed ungulates
This section is an excerpt from Artiodactyl § Genitourinary system.[edit]

The penises of even-toed ungulates have an S-shape at rest and lie in a pocket under the skin on the belly. The corpora cavernosa are only slightly developed; and an erection mainly causes this curvature to extend, which leads to an extension, but not a thickening, of the penis. Cetaceans have similar penises.[14] In some even-toed ungulates, the penis contains a structure called the urethral process.[15][16][17]

The testicles are located in the scrotum and thus outside the abdominal cavity. The ovaries of many females descend—as the testicles descend of many male mammals—and are close to the pelvic inlet at the level of the fourth lumbar vertebra. The uterus has two horns (uterus bicornis).[14]

Birds

Main article: Bird anatomy § Reproductive system

Male and female birds have a

mammals' penis. The female lays amniotic eggs in which the young fetus continues to develop after it leaves the female's body. Unlike most vertebrates, female birds typically have only one functional ovary and oviduct.[18]
As a group, birds, like mammals, are noted for their high level of parental care.

Reptiles

Main article:
Reptiles § Reproduction

eggs while others are ovoviviparous (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
.

A male common frog in nuptial colors waiting for more females to come in a mass of spawn

Amphibians

Main article: Amphibian § Reproduction

Most amphibians exhibit external fertilization of eggs, typically within the water, though some amphibians such as caecilians have internal fertilization.[19] All have paired, internal gonads, connected by ducts to the cloaca.

Fish

Main article: Fish reproduction

livebearers.[21]

Fish gonads are typically pairs of either ovaries or testicles. Most fish are sexually dimorphic but some species are

unisexual.[22]

Invertebrates

See also: Reproductive system of gastropods and Reproductive system of planarians

hermaphroditic and exhibit external fertilization
.

Cephalopods

Main article: Cephalopod § Reproduction and life cycle

All

ova found in the female's single ovary.[23] Likewise, male cephalopods have only a single testicle. In the female of most cephalopods the nidamental glands
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 transfer the spermatophores directly to the female.

Insects

Main article: Insect reproductive system

Most

fertilization, the eggs travel along oviducts to be fertilized by the sperm and are then expelled from the body ("laid"), in most cases via an ovipositor
.

Arachnids

Main article:
Arachnids § Reproduction
See also: Opiliones penis

Arachnids may have one or two gonads, which are located in the abdomen. The genital opening is usually located on the underside of the second abdominal segment. In most species, the male transfers sperm to the female in a package, or spermatophore. Complex courtship rituals have evolved in many arachnids to ensure the safe delivery of the sperm to the female.[24]

Arachnids usually lay yolky

viviparous
, depending on species, and bear live young.

Plants

Main article: Plant reproductive morphology
Further information: Sex organ § Plants

Among all living organisms,

abiotic
interactions.

Fungi

Main article:
Fungi § Reproduction
Further information: Sex organ § Fungi

Fungal reproduction is complex, reflecting the differences in lifestyles and genetic makeup within this diverse kingdom of organisms.

anamorph.[27] Environmental conditions trigger genetically determined developmental states that lead to the creation of specialized structures for sexual or asexual reproduction. These structures aid reproduction by efficiently dispersing spores or spore-containing propagules
.

See also

References

  1. ^ Introduction to the Reproductive System, Epidemiology and End Results (SEER) Program. Archived October 24, 2007, at the Wayback Machine
  2. ^ Reproductive System 2001 Body Guide powered by Adam
  3. ^ STD's Today Archived 2014-10-25 at the Wayback Machine National Prevention Network, Center for Disease Control, United States Government, retrieving 2007
  4. ^ Sexual Reproduction in Humans. Archived 2018-02-17 at the Wayback Machine 2006. John W. Kimball. Kimball's Biology Pages, and online textbook.
  5. ^ Schultz, Nicholas G., et al. "The baculum was gained and lost multiple times during mammalian evolution." Integrative and comparative biology 56.4 (2016): 644-656.
  6. PMID 9892556
    .
  7. ISBN 978-0-643-06257-3
    .
  8. ISBN 978-0-323-14620-3
    .
  9. ISBN 0-521-33792-5
    .
  10. ISBN 978-1-13675-363-3
    . Retrieved November 10, 2023.
  11. ISBN 978-1-60732-048-7
    . Retrieved November 10, 2023.
  12. ISBN 978-0-22692-532-5
    . Retrieved November 10, 2023.
  13. ^ Kotpal 2010, p. 394
  14. ^
    ISBN 978-3-8304-1075-1
    .
  15. ^ Spinage, C. A. "Reproduction in the Uganda defassa waterbuck, Kobus defassa ugandae Neumann." Journal of reproduction and fertility 18.3 (1969): 445-457.
  16. ^ Yong, Hwan-Yul. "Reproductive System of Giraffe (Giraffa camelopardalis). Archived 25 April 2019 at the Wayback Machine" Journal of Embryo Transfer 24.4 (2009): 293-295.
  17. ^ Sumar, Julio. "Reproductive physiology in South American Camelids." Genetics of Reproduction in Sheep (2013): 81.
  18. ^ Ritchison. BIO 554/754 Ornithology. Eastern Kentucky University.
  19. ASIN B000HHFY52
    .
  20. ^ Fish Reproduction
  21. ^ Science, Biology, and Terminology of Fish reproduction: Reproductive modes and strategies-part 1 Archived 2007-11-08 at the Wayback Machine. 2002. MARTIN MOE. THE BREEDER'S NET Online Magazine
  22. ^ Bony Fish Reproduction Archived 2007-09-27 at the Wayback Machine 2002. SeaWorld/Busch Gardens Animal Information Database.
  23. ^ Cephalopods. Archived 2007-10-20 at the Wayback Machine The Living World of Molluscs. Robert Nordsieck.
  24. ISBN 0-03-056747-5
    .
  25. S2CID 7424193. Archived from the original
    (PDF) on 2013-05-27. Retrieved 2015-06-05.
  26. ^ Alexopoulos et al., pp. 48–56.
  27. ^ Kirk et al., p. 633.

Cited literature

External links

Wikimedia Commons has media related to Reproductive system.
The Wikibook Human Physiology has a page on the topic of: The male reproductive system
The Wikibook Human Physiology has a page on the topic of: The female reproductive system
The Wikibook Anatomy and Physiology of Animals has a page on the topic of: Reproductive System
Library resources about
Reproductive system
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