Genital tubercle

A genital tubercle or phallic tubercle is a body of tissue present in the development of the reproductive system. 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 4 of gestation, and by week 9 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),[2] the term genital tubercle remains, but only as the terminal end of it,[3] which develops into either the glans penis or the glans clitoridis.

Genital tubercle
Stages in the development of the external sexual organs in the male and female.
Details
Precursorsomatopleure[1]
Gives rise togenital swelling, mons pubis, clitoris, penis
SystemReproductive system
Identifiers
Latintuberculum phallicum; tuberculum genitale
TEtubercle_by_E5.7.4.0.1.0.1 E5.7.4.0.1.0.1
Anatomical terminology

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.[4] 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.[5] 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.

See also

References

  1. Netter, Frank H.; Cochard, Larry R. (2002). Netter's Atlas of human embryology. Teterboro, N.J: Icon Learning Systems. p. 159. ISBN 0-914168-99-1.
  2. Netter, Frank (2022). Netter Atlas of Human Anatomy: Classic Regional Approach - Ebook. Elsevier Health Sciences. p. 194. ISBN 978-0-32379-375-9. Retrieved October 9, 2023.
  3. The University of North Carolina at Chapel Hill - Embryo images nr 024
  4. Joseph, Diya B.; Vezina, Chad M. (2018), "Male Reproductive Tract: Development Overview", Encyclopedia of Reproduction, Elsevier, pp. 248–255, doi:10.1016/B978-0-12-801238-3.64366-0, ISBN 9780128151457, retrieved 2023-01-04
  5. 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. doi:10.1016/j.diff.2018.08.001. ISSN 1432-0436. PMC 6234061. PMID 30249413.
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