Theca Cell

Definition - What does Theca Cell mean?

Theca cells are a layer of cells that form around a developing ovarian follicle and play an important role in the development of the ovarian follicle and formation of the corpus luteum. They are derived from the connective tissue of the ovary. These cells produce androgen hormones and regulate the production of estrogen by the granulosa cells, both of which are vital for proper reproductive function. Abnormalities of the theca cells is a leading cause of hormone-related infertility in females.

FertilitySmarts explains Theca Cell

The theca is made of two distinct layers, the theca interna and the theca externa.

Theca externa is primarily comprised of fibrous connective tissue and smooth muscle cells. Theca externa provides structural support to the follicle. The contraction of smooth muscle cells in the theca externa in response to the surge of luteinizing hormone (LH) during midcycle helps the rupture of the follicle and the subsequent release of the egg to the fallopian tube (ovulation).

Theca interna is the innermost and the cellular layer of the theca. The theca cells are very important for reproductive function in females. Theca cells produce androgen hormones in small amounts along with the substrate that is needed for the granulosa cells to produce estrogen and thus indirectly regulates estrogen production. Theca cells also nourish the follicle by providing granulosa cells and the egg with oxygen and nutrients. As the follicle transforms into the corpus luteum after the release of the egg, the theca cells in the follicle become the theca lutein cells of the corpus luteum. Theca lutein cells produce progesterone that is vital in keeping the reproductive tract prepared for implantation of the fertilized egg.

Over-activity of theca cells lead to a condition called hyperandrogenism, which is characterized by increased androgen hormone levels in the blood. Reduced activity of theca cells can reduce estrogen production by the granulosa cells. These are common causes of infertility in females.

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