Lecture Notes: Oogenesis and Reproductive Anatomy

Oogenesis and Meiosis

• Oogonium: The initial stage in oocyte development.
• Primary Oocyte: Begins meiosis I during fetal development.
• At Puberty:
  • Primary oocytes complete meiosis I, producing a secondary oocyte and the first polar body.
  • The secondary oocyte begins meiosis II, halting at metaphase.
  • Fertilization by sperm causes completion of meiosis II, resulting in an ovum and a second polar body.
  • Egg and sperm unite if fertilization occurs.

Follicle Development

• Primordial Follicles: Present in utero.
• Puberty:
  • Transition from primary to secondary follicles.
  • Oocyte develops into a secondary oocyte.

Follicular Structure

• Zona Pellucida: Surrounds oocyte.
• Granulosa Cells: Form Corona Radiata.
• Antrum: Fluid-filled, aids in oocyte maturation.

Ovulation

• Corpus Hemorrhagicum: Forms post-ovulation as the oocyte ruptures.
• Oocyte Release:
  • Enters pelvic cavity.
  • Fimbriae of uterine tube coax oocyte into tube.

Movement Through the Uterine Tube

• Fimbriae: Finger-like projections that sweep oocyte into the tube.
• Movement Mechanisms:
  • Peristalsis: Muscle contractions move the oocyte.
  • Ciliary Action: Ciliated cells assist movement.
• Uterine Tube Regions:
  • Infundibulum: Funnel-shaped region with fimbriae.
  • Ampulla: Fertilization typically occurs here.
  • Isthmus: Narrow region before the uterus.
• Fertilization: Must occur within 24 hours of ovulation.
• Zygote Travel: Reaches uterus approximately 7 days post-ovulation.

Support Structures and Anatomy

• Ligaments:
  • Suspensory ligament: Attaches to uterine tube.
  • Broad ligament: Connects to sides.
  • Utero-sacral ligament: Provides support.
• Uterine Cavity: Location within the uterus.
• Vagina: Part of the reproductive tract.

Uterine Tube Layers

1. Mucosa
2. Muscularis
3. Serosa

Goals for Lecture Six

• Describe ovarian and uterine tube anatomy.
• List stages of oocyte and follicle development.
• Define key terms related to follicular and oocyte development:
  • Graafian follicle, primordial follicle, ovarian cyst, corpus luteum, corpus hemorrhagicum, corpus albicans.
  • Primary oocytes, secondary oocyte, polar body, oogonium, primary follicle, secondary follicle.
  • Atresia, zona pellucida, corona radiata, antrum.
• Draw and label ovary and uterine tube components, including fimbriae, ampulla, isthmus, infundibulum.
• Describe ovulation and mechanisms for oocyte movement through the uterine tube.