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The development of the gonads is part of the prenatal development of the reproductive system and ultimately forms the testicles in males and the ovaries in females. The immature ova originate from cells from the dorsal endoderm of the yolk sac. Once they have reached the gonadal ridge they are called oogonia.
Because primordial follicles can be dormant for up to 50 years in humans, the length of the ovarian cycle does not include this time. The supply of follicles decreases slightly before birth, and to 500,000 by puberty for the average case (populations at puberty range from 25,000 to 1.5 million). [4]
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.
A gonad, sex gland, or reproductive gland [1] is a mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. [2]
The reverse is true for the Müllerian duct, as it essentially disappears in the male reproductive system and forms the fallopian tubes, uterus, and vagina in the female system. In both sexes, the gonads go on to form the testes and ovaries; because they are derived from the same undeveloped structure, they are considered homologous organs ...
The ovaries lie within the peritoneal cavity, on either side of the uterus, to which they are attached via a fibrous cord called the ovarian ligament. The ovaries are uncovered in the peritoneal cavity but are tethered to the body wall via the suspensory ligament of the ovary , which is a posterior extension of the broad ligament of the uterus.
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]
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 described together as the genitourinary system.