important stuff

• FSH decreases due to oestradiol feedback from growing follicles. The dominant follicle will produce specific growth factors and increase LH receptors to become more receptive to LH
• The LH surge results in proliferation of the cumulus oocyte complex (specialised granulosa cells) which nourish the oocyte. Meiosis resumes from prophase i to metaphase ii then arrests again (the oocyte progresses from a primary oocyte to a secondary oocyte at this point).

  There is an inflammatory reaction in the follicle wall causing rupture (ovulation) and the broken BVs allow blood to flow into the post-ovulatory follicle, forming the corpus haemorrhagicum. Granulosa and theca cells differentiate into luteal cells to form the corpus luteum. The large luteal cells produce progesterone
• Oestrogens prepare for parturition by:

  • synthesis of contraction associated proteins
  • synthesis of myometrial stimulants PGE2, PGF2a
  • stimulates CL and pituitary oxytocin release
  • synthesis of collagenases
  • synthesis of relaxin in the CL (pig) or placenta (horse/carnivores)