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In invertebrates and plants, hermaphrodites (which have both male and female reproductive organs either at the same time or during their life cycle) are common, and in many cases, the norm. In other varieties of multicellular life (e.g. the fungi division, Basidiomycota ), sexual characteristics can be much more complex, and may involve many ...
Despite the differences between them, the adult male and female are determined in early development in the 6th week. The gonads and external genitals are derived from the intermediate mesoderm. [7] The three main fetal precursors of the reproductive organs are the Wolffian duct, the Müllerian ducts, and the gonads.
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.
Differentiation between the sexes of the sex organs occurs throughout embryological, fetal and later life. In both males and females, the sex organs consist of two structures: the internal genitalia and the external genitalia. In males, the gonads are the testicles and in females, they are the ovaries.
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]
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 life cycle of land plants involves alternation of generations between a sporophyte and a haploid gametophyte. [25] The gametophyte produces sperm or egg cells by mitosis. The sporophyte produces spores by meiosis, which in turn develop into gametophytes. Any sex organs that are produced by the plant will develop on the gametophyte.
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.