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ot. The genital ridge from which either the ovary or testis is formed. o. The left ovary: t. Testis in the place of its original formation; t', together with the dotted lines above, indicates the direction in which the testis and epididymis descend from the abdomen into the scrotum. Skene's glands a.k.a. paraurethral gland: pr. Prostate: u. Uterus.
The ovary is thus formed mainly from the genital ridge and partly from the mesonephros. Later the mass is differentiated into a central part, the medulla of ovary, covered by a surface layer, the germinal epithelium. Between the cells of the germinal epithelium a number of larger cells, the immature ova, are found.
A testicle or testis (pl. testes) is the gonad in all male bilaterians, including humans, and is homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of androgens, primarily testosterone. The release of testosterone is regulated by luteinizing hormone (LH) from the anterior pituitary gland.
Since the scrotum, where the testes is present, is situated outside the body cavity, it provides a temperature about 3 °C below normal body temperature. In females, gametogenesis is known as oogenesis; this occurs in the ovarian follicles of the ovaries. This process does not produce mature ovum until puberty.
In animals (including humans), the male sex organs include the testicles, epididymides, and penis; the female sex organs include the clitoris, ovaries, oviducts, and vagina. The testicle in the male and the ovary in the female are called the primary sex organs. [1] All other sex-related organs are known as secondary sex organs.
The testes of older men often have sperm abnormalities that can ultimately lead to male infertility. [12] These abnormalities include accumulation of DNA damage and decreased DNA repair ability. [12] During spermatogenesis in the testis, spontaneous new mutations arise and tend to accumulate with age. [13]
Gonadal sex refers to the gonads, that is the testicles or ovaries, depending on which genes are expressed. Phenotypic sex refers to the structures of the external and internal genitalia. [6] Six weeks elapse after fertilization before the first signs of sex differentiation can be observed in human embryos. [5]
Sexual differentiation is the process of development of the sex differences between males and females from an undifferentiated zygote. [1] [2] Sex determination is often distinct from sex differentiation; sex determination is the designation for the development stage towards either male or female, while sex differentiation is the pathway towards the development of the phenotype.