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Reproductive System Development (view source)
Revision as of 11:26, 22 August 2011
, 11:26, 22 August 2011→Pregonadal Phase
===Pregonadal Phase===
===Pregonadal Phase===
The pregonadal phase represents the stage where '''germ cells''' begin to migrate from the yolk sac of the developing embryo. Primitive primordial germ cells are formed in the yolk sac (the yolk sac is part of the digestive system in the embryo). These primitive germ cells migrate from the yolk sac through the mesentry to the '''genital ridges''' which are small elongated pieces of tissue beneath the peritoneum situated at the dorsal aspect of the abdominal cavity. These germ cells then begin to divide by mitosis and the gonads are developed from these genital ridges.
The pregonadal phase represents the stage where '''germ cells''' begin to migrate from the yolk sac of the developing embryo. Primitive primordial germ cells are formed in the yolk sac (the yolk sac is part of the digestive system in the embryo). These primitive germ cells migrate from the yolk sac through the mesentry to the '''genital ridges''' which are small elongated pieces of tissue beneath the peritoneum situated at the dorsal aspect of the abdominal cavity. These germ cells then begin to divide by mitosis and the gonads are developed from these genital ridges.
====Migration & Proliferation of Germ Cells====
Germs cells migrate via an amoeboid movement. These germs cells travel from the primitive streak in the yolk sac to the allantois, then to the hind gut before reaching the urogenital ridge and gonads. In the male the XY germ cells undergo mitosis from leaving the primitive streak until reaching the urogenital ridge and/or the gonads. At this stage the XY germ cells
===Bipotential Gonadal Phase===
===Bipotential Gonadal Phase===