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Development of the gonads. 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.
A typical sea anemone is a sessile polyp attached at the base to the surface beneath it by an adhesive foot, called a basal or pedal disc, with a column-shaped body topped by an oral disc. Most are from 1 to 5 cm (0.4 to 2.0 in) in diameter and 1.5 to 10 cm (0.6 to 3.9 in) in length, but they are inflatable and vary greatly in dimensions.
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 male gonad, the testicle, produces sperm in the form of spermatozoa. The female gonad, the ovary, produces egg cells.
The male reproductive system consists of a number of sex organs that play a role in the process of human reproduction. These organs are located on the outside of the body, and within the pelvis. The main male sex organs are the penis and the scrotum, which contains the testicles that produce semen and sperm, which, as part of sexual intercourse ...
Germ layer. A germ layer is a primary layer of cells that forms during embryonic development. [ 1 ] The three germ layers in vertebrates are particularly pronounced; however, all eumetazoans (animals that are sister taxa to the sponges) produce two or three primary germ layers.
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. Endocrine hormones are a well-known and critical controlling factor in the normal differentiation of the reproductive system. [8]
2 and 5 sex cords. A depiction of the migration of the cells which will give rise to the sex cords into the genital ridge where they will become the gonads of the embryo. Sex cords are embryonic structures which eventually will give rise (differentiate) to the adult gonads (reproductive organs). [ 1 ] They are formed from the genital ridges ...
Coelomic epithelium. Coelomic epithelium refers to the epithelium that lines the surface of the body wall and abdominal organs. It constitutes the outermost layer of the male and female gonads, thus forming the germinal epithelium of the female or of the male. It is also called the germinal epithelium of Waldeyer or sometimes the superficial ...