Blastema

A blastema (from the Greek blastos "sprout", "germ") is an early embryonic organ system that presents itself in the form of an undifferentiated mesenchyme compression. In the development of the blastema into a mature organ, proliferation , differentiation and morphogenetic cell movements play a major role. In addition, the expression of specific cell adhesion molecules and the susceptibility to 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

Metanephrogenic blastema

Around the 33rd day after fertilization, at the level of the first sacral vertebra, the so-called ureter bud grows backwards from the ductus mesonephricus . This bud induces a compression in the mesenchyme called metanephrogenic blastema . The ureter bud grows further into the blastema and branches dichotomously . The urinary tract of the later kidney emerges from it .

The fetal metanephrogenic blastema develops into regular kidney parenchyma with glomerula and tubules of the kidney during pregnancy . In about 1% of the kidneys, residual nephrogenic tissue can be found during an autopsy as the persistence of this metanephrogenic blastema.

A persistence of blastematic tissue is considered a precancerous condition (for nephroblastoma ) and is called nephroblastomatosis .

Cardiogenic blastema

At about the 25th day after fertilization walk from the central region of the primitive streak cells and form between the cranial end of the embryonic and prechordal plate the so-called cardiogenic blastema . This lies in a U-shape in front of the head fold . The heart arises from it .

Individual evidence

1. ↑ GJ Lonergan, MI Martínez-León, GA Agrons, H. Montemarano, ES Suarez: Nephrogenic rests, nephroblastomatosis, and associated lesions of the kidney. In: RadioGraphics. 18, 1998, p. 947, doi : 10.1148 / radiographics.18.4.9672980 .
2. ↑ P. Reimer, PM Parizel, F.-A. Stichnoth (Editor): Clinical MR Imaging. A practical approach. Springer, 2nd edition 2006, ISBN 3-540-31530-6 , p. 542

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !