VAN 211: Veterinary Histology and Embryology (2+2)

MECHANISM OF OVULATION

• As the follicle matures it bulges from the surface of the ovary. At the apex of the follicle an avascular spot appears and it is called stigma.
• The follicle ruptures at the stigma and the liquor folliculi is liberated carrying with it the ovum and the discus proligerous.

Theories of ovulation

• Pressure theory: As the follicle matures, the follicular fluid increases in quantity and the pressure brings about the rupture of the follicle. This theory is not accepted in cow, ewe and sow where at the time of ovulation the follicle will be flabby but still ovulation occurs.
• Massage theory: The follicle ruptures by massage action, which lacks proof.
• Hormonal theory: The ovulation takes place by the influence of hormones and is the most accepted theory.