The urogenital opening is where bodily waste and reproductive fluids are expelled to the environment outside of the body cavity. In some organisms, including monotremes,[1] birds and many fish, discharge from the urological, digestive, and reproductive systems empty into a common sac called the cloaca.

In placental mammals, these three systems are more separated. In females, separate orifices have evolved for all three, while in males, a common urinary meatus discharges both urine and semen from the urethra.[2] In marsupials[3][4] and rabbits[5][6] and pigs, the female urethra and vagina open into a urogenital sinus with a common urogenital opening.[7]

References

edit
  1. ^ Withers, Philip C.; Cooper, Christine E.; Maloney, Shane K.; Bozinovic, Francisco; Neto, Ariovaldo P. Cruz (2016-10-27). Ecological and Environmental Physiology of Mammals. Oxford University Press. ISBN 978-0-19-109267-1.
  2. ^ Libbie Henrietta Hyman (15 September 1992). Hyman's Comparative Vertebrate Anatomy. University of Chicago Press. pp. 583–. ISBN 978-0-226-87013-7.
  3. ^ Nowak, Ronald M. (2005-09-12). Walker's Marsupials of the World. JHU Press. ISBN 978-0-8018-8211-1.
  4. ^ Withers, Philip C.; Cooper, Christine E.; Maloney, Shane K.; Bozinovic, Francisco; Neto, Ariovaldo P. Cruz (2016-10-27). Ecological and Environmental Physiology of Mammals. Oxford University Press. ISBN 978-0-19-109267-1.
  5. ^ Smith, David G.; Schenk, Michael P. (2019-02-01). A Dissection Guide & Atlas to the Rabbit. Morton Publishing Company. ISBN 978-1-61731-938-9.
  6. ^ Lukefahr, Steven D.; McNitt, James I.; Cheeke, Peter R.; Patton, Nephi M. (2022-04-29). Rabbit Production, 10th Edition. CABI. ISBN 978-1-78924-978-1.
  7. ^ Smith, David G.; Schenk, Michael P. (2014-01-01). Exploring Zoology: A Laboratory Guide. Morton Publishing Company. ISBN 978-1-61731-157-4.