Spermatogenesis spermatogonium spermatocyte spermatid sperm Oogenesis oogonium oocyte ootid ovum Germ cell gonocyte gamete. The testes begin to secrete three hormones that influence the male internal and external genitalia. In females, the mesonephric ducts regress. The mesonephric duct MD grows on the lateral side of the mesonephros Msthen crosses medially to the gonadal ridge.
In embryos with an XY sex gonadal sex differentiation in Edmonton complex, medullary cords develop into testis cords and secondary cortical cords fail to develop. Publication types Review. The indifferent gonad now consists of an outer cortex and an inner medulla.
The type of gonads present then determines the type of sexual differentiation that occurs in the genital ducts and external genitalia. Hence, sex-determining genes may operate not only in the gonads, to produce testes or ovaries, but also throughout cells of the body.
By the time of the third month, primordial follicles are generated as the cortical cords divide into isolated cell clusters that proliferate and later start to surround the primordial female reproductive cells oogonia with a layer of epithelial cells called follicular cells.
Chromosomal and genetic sex is established at fertilization and depends upon whether an X-bearing sperm or a Y-bearing sperm fertilizes the X-bearing ovum. In embryos with an XY sex chromosome complex, the medulla differentiates into a testis and the cortex regresses.
Gonadal sex differentiation in Edmonton are almond shaped bodies, found in pairs in the female reproductive system whose main functions are: the production of hormones estrogen and progesterone and oogonia the female reproductive cells.
In embryos with an XY sex chromosome complex, the medulla differentiates into a testis and the cortex regresses. It contains the testis-determining gene, the SRY sex-determining region on Gonadal sex differentiation in Edmonton gene on its short arm Yp These efferent ductules are the remaining parts of the excretory gonadal sex differentiation in Edmonton of the mesonephric system.
It is the androgen testosterone, produced by the testes, that determines maleness. In the 4th month major changes happens: testis cords become horseshoe-shaped with their extremities continuous with those of the rete testis and, at this time, they are composed of two types of cells gonadal sex differentiation in Edmonton sustentacular cells of Sertoli, involved in support and protection, and primitive germ cells, both derived from the surface epithelium of the gland.
Contrary to the male embryos, the medullary cords of the gonads of the female embryos regress and a secondary generation of cortical cords develops. If the embryo is genetically male contains both sex chromosomes, X and Y chromosomethe signal for testis development is mediated by the SRY gene on the Y chromosome.
Genes carried on one or both of these sex chromosomes control sexual differentiation during embryonic life, producing testes in males ZZ and ovaries in females ZW.
Ditewig, Yao consider the process of ovary organogenesis as the default organ, which develops in the absence of testis-promoting factors. By 7 weeks, a fetus has a genital tubercle , urogenital groove and sinus, and labioscrotal folds. Many of these cases suggest some genetic or hormonal effect on sex differentiation of behavior and mental traits  this has been disputed as poor interpretation of scientific methodology.
Primitive gonads are formed by the proliferation of germ cells, which migrate from the yolk sac and undergo condensation of the underlying mesenchyme in the sixth week.