Genital tubercle explained

Genital tubercle
Latin:tuberculum phallicum; tuberculum genitale
System:Reproductive system
Precursor:Somatopleure[1]
Givesriseto:Clitoris or penis

A genital tubercle, phallic tubercle, or clitorophallic structure[2] is a body of tissue present in the development of the reproductive system of amniotes.[3] It forms in the ventral, caudal region of mammalian embryos of both sexes, and eventually develops into a primordial phallus. In the human fetus, the genital tubercle develops around week four of gestation, and by week nine, becomes recognizably either a clitoris or penis. This should not be confused with the sinus tubercle which is a proliferation of endoderm induced by paramesonephric ducts. Even after the phallus is developed (either a penile shaft or clitoral shaft),[4] the term genital tubercle remains, but only as the terminal end of it,[5] which develops into either the glans penis or the glans clitoridis.

In the development of the male fetus, the two sides of the tubercle approach ventrally forming a hollow tube that encloses the male urethra. The two glans wings merge in the midline forming the septum glandis. In the female fetus, the tubercle is attached to the vestibular folds that remain unfused forming the labia minora and the vaginal vestibule in between.[6] The genital tubercle is sensitive to dihydrotestosterone and rich in 5-alpha-reductase, so that the amount of fetal testosterone present after the second month is a major determinant of phallus size at birth.

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Notes and References

  1. Book: Netter, Frank H. . Cochard, Larry R. . Netter's Atlas of human embryology . Icon Learning Systems . Teterboro, N.J . 2002 . 0-914168-99-1 . 159.
  2. Book: Skinner, Michael K.. Elsevier Science. 2018. Encyclopedia of Reproduction: Volume 1 . 445. 978-0-12815-145-7.
  3. Book: Prum, Richard O.. University of Chicago Press. 2023. Performance All the Way Down: Genes, Development, and Sexual Difference . 219. 978-0-22682-978-4 .
  4. Book: Netter, Frank. Elsevier Health Sciences . 2022. Netter Atlas of Human Anatomy: Classic Regional Approach - Ebook. 194. October 9, 2023 . 978-0-32379-375-9 .
  5. Web site: Urogenital Development - External Genitalia 24 of 28 . live . https://web.archive.org/web/20110411041212/http://www.med.unc.edu/embryo_images/unit-genital/genital_htms/genital024.htm . Apr 11, 2011 . Units of Embryo Images . UNC School of Medicine.
  6. Baskin . Laurence . Shen . Joel . Sinclair . Adriane . Cao . Mei . Liu . Xin . Liu . Ge . Isaacson . Dylan . Overland . Maya . Li . Yi . Cunha . Gerald R. . 2018 . Development of the human penis and clitoris . Differentiation; Research in Biological Diversity . 103 . 74–85 . 10.1016/j.diff.2018.08.001 . 1432-0436 . 6234061 . 30249413.