Ovulation

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Ovulation
Chapter 7
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Schematic outline of the ovulatory process.
LH
cAMP
()
()
PA
PG
Vascular permeability
Plasminogen
Plasmin
Procollagenase
()
Maintenance of positive intrafollicular prressure
driving force for extrusion of oocyte
Collagenase
(Further cleavage of collagen)
Weakening of follicle wall
Collagen breakdown
Ovulation
PA Plasminogen activator PG Prostaglandins
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Biochemical mediators in ovulation and their main
effects on the follicle.
LH
PA
PG
NO
Ang II
Weakening of follicular wall
Vascular permeability
Blood flow
Positive intrafollicular pressureDriving force
at oocyte extrusion
Ovulation
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Mechanisms of Ovulation

• 1. Endocrine mechanisms
• steroids switch from 2.0? 0.15 (EP ratio)
• LH
• Prostaglandins
• 2. Neurobiochemical mechanisms
• Plasmin formation
• theca collagenase
• lysome rupture

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• 3. Neuromuscular mechanisms-
• PGF2? release occurs 30-40h after LH surge
• 1. Inhibition of PGF2? production inhibits
  ovulation

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• Cyclic activity
• Spontaneous ovulators Continually
  polyestrous
• Seasonal polyestrous
• Induced ovulators
• Monoestrous

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Anomalies of Ovulation (Dairy Cattle)

• 1. Cystic follicles - GnRH?LH
• hCG ? ovary
• 2. Why Some problem with gonadotropic release-
  not receptors- hCG causes ovulation

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Cystic Follicle