Resumen

CASTEJON, Olivar C. La lámina basal trofoblástica y su relación con la ultraestructura del trofoblasto. Gac Méd Caracas [online]. 2005, vol.113, n.1, pp.59-64. ISSN 0367-4762.

To evaluate the trophoblastic basement membrana in placental villi at term specimens were taken from five placentas inmediately after normal vaginal delivery to be processed according to conventional transmission electron microscopy and the Gaboul method to determine polyanionic sites with the alcian blue. The findings showed a densa lamina of variable trickness, uniform, closely associated to the trophoblastic plasma membrane. The lucid lamina was absent. The fibrils of collagen contact the dense lamina throughout the stromal suface. In regions of increased trophoblastic biosynthetic acti-vity the dense lamina suffers important changes, lose uniformity and emits extensions in both surfaces. The Gaboul method determined absence of anionic sites in the dense lamina indicating a free transport of macromolecules to the fetal capillary compartment. This trophoblastic activity seems to change the thickness and the structure of the dense lamina.

Palabras clave : Trophoblastic; basement membrane.; Villi. Human placenta.