Theca of follicle

Diagram of a mature ovarian follicle. The theca cells are represented by the outer layer.

The Theca of follicle refers to a group of cells in the ovary that play a crucial role in the development of the ovarian follicle, which is essential for female reproduction. The theca cells are divided into two layers: the theca interna and the theca externa.

Structure

The theca cells form a layer around the ovarian follicle. The theca interna is the inner layer, which is vascular and produces hormones. The theca externa is the outer layer, which is fibrous and provides structural support.

Theca Interna

The theca interna cells are steroidogenic, meaning they produce steroid hormones. These cells express LH receptors and respond to LH stimulation by producing androstenedione, a precursor to estrogen.

Theca Externa

The theca externa cells are fibroblast-like and provide structural support to the follicle. They also have contractile properties that may facilitate ovulation.

Function

The primary function of the theca cells is to produce androgens, in response to LH stimulation. These androgens are then converted into estrogens by the granulosa cells of the follicle, under the influence of FSH.

Clinical Significance

Abnormalities in theca cell function can lead to reproductive disorders such as PCOS. In PCOS, the theca cells produce excessive amounts of androgens, leading to an imbalance in hormone levels.

See Also

• Ovarian follicle
• Luteinizing hormone
• Follicle-stimulating hormone
• Polycystic ovary syndrome