Blastema

A blastema (from Greek blastos "sprout ", "seed" ) is an early embryonic primordium, which presents itself in the form of an undifferentiated mesenchymal condensation. In the development of the blastema to the mature organ proliferation, differentiation and morphogenetic cell movements play a major role. In addition, expression of specific cell adhesion molecules and susceptibility play against paracrine ( secreted by neighboring cells) and autocrine ( secreted by the cell itself ) Growth factors play an important role in the differentiation of the organ system.

Examples

Metanephrogenes blastema

To the 33rd day after fertilization grows at the level of the first sacral vertebra from the mesonephric duct called the ureteric bud back from. This bud mesenchyme induces a compression, which is called metanephrogenes blastema. The ureteric bud grows further into the blastema and branched dichotomously. From it arise the lower urinary tract of the later kidney. The metanephric blastema forms the glomeruli and tubules of the kidney.

Cardiogenic blastema

At about the 25th day after fertilization migrate from the central region of the primitive streak of cells and form between the cranial end of the embryonic and the prechordal plate, the so-called cardiogenic blastema. This is U-shaped in front of the head fold. From his heart is formed.

• Organogenesis