Tags: Anatomical Structure.
The theca externa is the outer layer of the theca folliculi. It is derived from connective tissue the cells resembling fibroblasts and contains abundant collagen. During ovulation the surge in luteinizing hormone increases cAMP which increases progesterone and PGF2α production. The PGF2α induces the contraction of the smooth muscle cells of the theca externa increasing intrafollicular pressure.