Corpus Luteum Formation After Ovulation
After ejecting a mature ovum, the ovarian follicle develops into the corpus luteum (Answer C). This transformation represents a fundamental physiological process in the ovarian cycle, where the ruptured follicle undergoes luteinization to form a highly vascular, progesterone-secreting endocrine structure 1, 2.
The Luteinization Process
Following ovulation, the preovulatory follicle undergoes a complex transformation involving both granulosa and theca interna cells:
- Granulosa cells form the bulk of the corpus luteum and differentiate into large steroidogenic luteal cells 2
- Theca interna cells differentiate into small steroidogenic luteal cells 2
- This transformation is triggered by the preovulatory LH surge, which initiates morphological, endocrinological, and biochemical changes associated with luteinization 2
Key Physiological Changes
The corpus luteum represents a direct continuation of preovulatory follicle development with distinct functional characteristics:
- Steroid production shifts from estrogen secretion (characteristic of the follicle) to progesterone secretion (characteristic of the corpus luteum) 1
- Vascular development occurs through breakdown of the follicular basement membrane, endothelial cell migration and proliferation, creating a highly vascular structure 2
- Cell hypertrophy and hyperplasia occur as follicular cells transform into luteal cells capable of secreting large quantities of progesterone 2
Clinical Significance
The corpus luteum has a fixed lifespan that varies by species and is essential for early pregnancy maintenance:
- The corpus luteum secretes elevated amounts of progesterone for a species-specific time period 1
- Adequate preovulatory FSH and LH exposure is required for the eventual corpus luteum to function normally and secrete appropriate progesterone levels 1
- In the absence of pregnancy, the corpus luteum undergoes regression (luteolysis) through apoptotic pathways 3
Why Other Options Are Incorrect
- Atretic follicle (A): This represents follicles that undergo degeneration without ovulating—the vast majority of follicles that stop developing after antrum formation 3
- Theca follicle (B): This is not a recognized developmental stage; theca cells are a component of follicles that contribute to corpus luteum formation 2
- Functional scar (D): While the corpus luteum eventually regresses and leaves scar tissue (corpus albicans), this is not the immediate post-ovulatory structure 3