The LH surge triggers ovulation approximately 36–44 hours later. Which cellular change within the dominant follicle causes the physical rupture of the follicle wall at ovulation?
- A Increased intrafollicular hydrostatic pressure from rapid fluid accumulation
- B Mechanical contraction of smooth muscle in the theca layer
- C LH-induced prostaglandin and plasminogen activator release causing proteolytic digestion and remodelling of the follicle wall (matrix metalloproteinase activation) ✓
- D Progesterone-induced apoptosis of granulosa cells weakening the follicle wall
Correct answer: C. LH-induced prostaglandin and plasminogen activator release causing proteolytic digestion and remodelling of the follicle wall (matrix metalloproteinase activation)
Explanation
The LH surge stimulates granulosa and theca cells to produce prostaglandins (PGE2, PGF2α) and activators of plasminogen (tissue-type plasminogen activator), which generates plasmin. Plasmin and matrix metalloproteinases (MMPs) degrade collagen in the follicle wall, weakening it. Prostaglandins also stimulate smooth muscle contraction in the ovarian stroma, assisting egg expulsion. This is why NSAIDs (COX inhibitors) can inhibit ovulation — a mechanism relevant to emergency contraception physiology.
Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.