A genital tubercle or phallic tubercle is a body of tissue present in the

development of the reproductive system The development of the reproductive system is the part of embryonic growth that results in the sex organs and contributes to sexual differentiation. Due to its large overlap with development of the urinary system, the two systems are typically ...

. It forms in the ventral, caudal region of

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

ian

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

s of both

sex Sex is the trait that determines whether a sexually reproducing animal or plant produces male or female gametes. Male plants and animals produce smaller mobile gametes (spermatozoa, sperm, pollen), while females produce larger ones ( ova, of ...

es, and eventually develops into a

primordial phallus In embryology, the primordial phallus refers to the clitoris of a female or the penis in the male, particularly during fetal development of the urinary and reproductive organs, before sexual differentiation is evident. This is also the case for ...

. In the human

fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal deve ...

, the genital tubercle develops around week 4 of

gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregna ...

, and by week 9 becomes recognizably either a

clitoris The clitoris ( or ) is a female sex organ present in mammals, ostriches and a limited number of other animals. In humans, the visible portion – the glans – is at the front junction of the labia minora (inner lips), above the ope ...

penis A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do n ...

. This should not be confused with the

sinus tubercle Sinus tubercle (also known as sinual tubercle or Müllerian eminence) is the proliferation of endoderm induced by the paramesonephric ducts. It is located in the developing fetus between the orifices of the mesonephric ducts on the urogenital s ...

which is a proliferation of

endoderm Endoderm is the innermost of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and mesoderm (middle layer). Cells migrating inward along the archenteron form the inner layer of the gast ...

induced by paramesonephric ducts. Even after the phallus is developed, the term genital tubercle remains, but only as the terminal end of it,The University of North Carolina at Chapel Hill - Embryo images nr 024
/ref> which develops into either the

glans penis In male human anatomy, the glans penis, commonly referred to as the glans, is the bulbous structure at the distal end of the human penis that is the human male's most sensitive erogenous zone and their primary anatomical source of sexual p ...

or the

glans clitoridis The glans (, plural "glandes" ; from the Latin word for "acorn") is a vascular structure located at the tip of the penis in male mammals or a homologous genital structure of the clitoris in female mammals. Structure The exterior structure of ...

. The genital tubercle is sensitive to

dihydrotestosterone Dihydrotestosterone (DHT, 5α-dihydrotestosterone, 5α-DHT, androstanolone or stanolone) is an endogenous androgen sex steroid and hormone. The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues includi ...

and rich in 5-alpha-reductase, so that the amount of fetal

testosterone Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testes and prostate, as well as promoting secondar ...

present after the second month is a major determinant of phallus size at birth.

References

External links

*
Overview at mcgill.ca
{{DEFAULTSORT:Genital Tubercle Embryology of urogenital system

See also

References

External links