Theca externa

Theca externa
File:Mature Graffian follicle.jpg
Mature late-stage tertiary (Graffian) follicle
File:Follicle histology.gif
Early folliculogenesis from primordial to early tertiary.
Latin	theca folliculi
Dorlands/Elsevier	t_07/12801620

The theca folliculi comprise a layer of the ovarian follicles. They appear as the follicles become tertiary follicles.

The theca are divided into two layers: theca interna and theca externa.

Theca interna

Theca interna cells express receptors for luteinizing hormone to produce androstenedione, which via a few steps, gives the granulosa the precursor for estrogen manufacturing.

After rupture of the mature ovarian follicle, the theca interna cells differentiate into the theca lutein cells of the corpus luteum. These cells secrete estradiol.

The theca externa is the outer layers of the theca folliculi. They contain abundant collagen and are mainly supportive.

v • d • e Female reproductive system
Follicles/Folliculogenesis	corpus (hemorrhagicum, luteum, albicans) • Theca folliculi (externa, interna) • Follicular antrum (Follicular fluid) • Corona radiata • Zona pellucida • Membrana granulosa (Granulosa cells)
Ovaries/Oogenesis	Germinal epithelium • Tunica albuginea • cortex (Cumulus oophorus, Stroma) • Medulla
Fallopian tubes	Isthmus • Ampulla • Infundibulum • Fimbria
Ligaments	Broad (components: Mesovarium, Mesosalpinx, Mesometrium contents: Round of uterus, Proper of ovary) • Suspensory of ovary • Cardinal
Uterus	cervix/neck (External orifice - Canal of the cervix, Internal orifice) • corpus/body (Cavity of the body, Fundus) • layers (Endometrium, Myometrium, Perimetrium) • Uterine horns
Vulva/mons pubis	Labium: commissures (Anterior • Posterior) • Frenulum labiorum pudendi • Labia majora • Cleft of venus • Labia minora • Vulval vestibule • interlabial sulci Clitoris: Vestibular bulbs • Clitoral crura • Corpus cavernosa • Clitoral glans (Frenulum, Hood) Vagina: vestibular glands/ducts (Bartholin's glands/Bartholin's ducts, Skene's glands/Skene's ducts) • Fossa of vestibule of vagina • Vaginal fornix • Hymen • Orifice
Vestiges	Wolffian (Gartner's duct, Epoophoron, Paroöphoron) • Canal of Nuck
Other	G-spot • Urethral sponge