Female Reproductive System Lecture Notes

Basics of Human Body Systems

• Many body systems are crucial for survival (muscular, skeletal, respiratory, circulatory).
• Reproductive system is unique: focuses on the propagation of genetic material rather than individual survival.

Key Components of the Reproductive System

• Gonads: Testes and ovaries.
• Gametes: Sperm and eggs.
• Hormones: Various sex hormones.
• Others: Glands, ducts, external genitalia, certain brain parts.

Female Anatomy

1. External Genitalia

   • Vulva: Includes mons pubis, labia majora, and labia minora.
   • Vagina: Passage for menstrual blood, babies, and sperm.

2. Internal Reproductive Organs

   • Ovaries: Produce and release gametes (eggs) and secrete hormones (estrogen, progesterone).
   • Structure of Ovaries
     • Tunica Albuginea: Connective tissue layer.
     • Germinal Epithelium: Layer of epithelial cells.
     • Cortex: Houses developing eggs.
     • Medulla: Contains blood vessels and nerves.

Reproductive Units: Ovarian Follicles

• Ovarian Follicles: Contain primary oocyte and supporting cells.
• Females are born with around 1 million primordial follicles.
• Oocytes pause their development at the first stage of meiosis and stay dormant until puberty.
• Oogenesis: The process of egg creation, delayed until the body is ready for reproduction.
• Eggs mature almost constantly, one at a time, unlike certain animals that mature all eggs at once.

Ovarian and Menstrual Cycles

1. Ovarian Cycle

   • Involves follicle and egg maturation.
   • Driven by sex hormones produced by the hypothalamus and pituitary gland.
   • Hormonal Stimulation
     • Gonadotropin-releasing Hormone (Hypothalamus) → Stimulates anterior pituitary.
     • Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH) (Anterior Pituitary).
   • FSH: Promotes growth of the leading follicle, which secretes estrogen.
   • Estrogen Surge: Triggers pituitary to release LH.
   • LH Surge: Finalizes oocyte maturation (completes meiosis I, moves to metaphase II).
   • Ovulation: Approximately 14 days, follicle ejects a mature oocyte.
   • Post-Ovulation: Follicle morphs into corpus luteum, secretes progesterone, estrogen, inhibin.

2. Uterine (Menstrual) Cycle

   • Prepares the uterus for a fertilized egg.
   • Three Phases
     • Menstrual Phase: Shedding of the functional endometrial layer.
     • Proliferative Phase: Endometrium regeneration, days 6-14.
     • Secretory Phase: Corpus luteum enhances endometrial thickening and nutrient secretion.
   • Key Events
     • If no fertilization: Endometrium is shed, corpus luteum degenerates.
     • If fertilization: Endometrium is sustained to support embryo implantation.

Summary and Conclusion

• In the next session: In-depth look at fertilization.
• Understanding reproductive anatomy, cycles, and the significant hormonal control involved.

Additional Credits

• Written by Kathleen Yale
• Consultants: Dr. Brandon Jackson
• Direction, Editing, Sound Design, Graphics: Various noted contributors
• Support: Patrons of Crash Course