The theca externa is the outer layer of the theca folliculi.

Outside the basal lamina, the layers theca interna and theca externa are found.

Some LHR immunoreactivity was also detected in theca externa cells (te).

The theca are divided into two layers, the theca interna and the theca externa.

The PGF2α induces the contraction of the smooth muscle cells of the theca externa, increasing intrafollicular pressure.

They surround the follicle's outermost layer, the basal lamina, and undergo cytodifferentiation to become the theca externa and theca interna.

The late-term secondary follicle is marked histologically by a fully grown oocyte surrounded by a zona pellucida, approximately nine layers of granulosa cells, a basal lamina, a theca interna, a capillary net, and a theca externa.

One group, which expresses BMP-4, is present as an outer layer of cells juxtaposed to the theca externa (TE), and another, which expresses BMP-7, is present at the proximal side of the theca interna near the basal lamina of the follicle.