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, the theca interna and the theca externa.
Theca interna cells express receptors
for luteinizing hormone
, which when activated will stimulate the production of androstenedione
from cholesterol by the enzyme desmolase
. Androstenedione ultimately gives the granulosa
the precursor for estrogen
After rupture of the mature ovarian follicle, the theca interna cells differentiate into the theca lutein cell of the corpus luteum. These cells secrete progesterone.
The theca externa is the outer layers of the theca folliculi. It contains contain abundant collagen
and is mainly supportive.
- - "Mammal, canine ovary (LM, High)"
- - "Mammal, bovine ovary (LM, Medium)"
- - interna
- - externa
- Slide at trinity.edu