Anatomy and Physiology of the Ovarian Reproductive System

Learning Objectives

• Understand the structure and function of the ovarian reproductive system.
• Describe the process of oogenesis.
• Explain hormonal changes during the ovarian and menstrual cycles.
• Trace the journey of an oocyte from ovary to fertilization.

Female Reproductive System Overview

• Functions: Produce gametes, reproductive hormones, support fetus development, and childbirth.
• Primarily located inside the pelvic cavity.
• Ovaries are female gonads producing oocytes.

External Female Genitals

• Collectively known as the vulva.
• Mons Pubis: Fat pad over pubic bone, covered in pubic hair post-puberty.
• Labia Majora and Minora: Protect urethra and entrance to reproductive tract.
• Clitoris: Important for sexual sensation.
• Hymen: Thin membrane, not indicative of virginity.
• Vaginal Opening: Between urethra and anus, flanked by Bartholins glands.

Vagina

• Muscular canal (~10 cm) for reproductive tract entry and uterine exit.
• Walls: Fibrous adventitia, smooth muscle, mucous membrane with rugae.
• Houses Lactobacillus bacteria for infection protection.
• Douching is discouraged to maintain microbial balance.

Ovaries

• Female gonads, almond-sized, located within pelvic cavity.
• Supported by mesovarium and suspensory ligament.
• Covered by ovarian epithelium and tunica albuginea.
• Composed of cortex (with ovarian stroma for oocyte development) and medulla (blood and lymph vessels, nerves).

The Ovarian Cycle

• 28-day cycle of oocyte and follicle changes.
• Oogenesis:
  • Begins with oogonia forming primary oocytes during fetal development.
  • Primary oocytes resume meiosis at puberty, transitioning to secondary oocytes.
  • Only one oocyte from oogenesis survives.
  • Secondary oocyte becomes ovum upon sperm penetration.

Folliculogenesis

• Development from primordial to tertiary follicles (~28 days).
• Primordial Follicles: Resting state, single layer of granulosa cells.
• Primary Follicles: Respond to signals, granulosa cells become cuboidal.
• Secondary Follicles: Increase in diameter, formation of zona pellucida and antrum.
• Tertiary Follicles: Fully developed, ready for ovulation.

Hormonal Control of Ovarian Cycle

• Involves GnRH, LH, and FSH.
• Follicular Phase: Growth and estrogen secretion by tertiary follicles.
• Ovulation: Triggered by LH surge; release of secondary oocyte.
• Luteal Phase: Corpus luteum secretes progesterone.
• If no pregnancy, corpus luteum becomes corpus albicans.

Uterine Tubes

• Conduits for oocyte from ovary to uterus.
• Consist of isthmus, infundibulum (with fimbriae), and ampulla.
• Layers: Serosa, smooth muscle, mucosal with ciliated cells.

Uterus and Cervix

• Muscular organ for embryo nourishment.
• Sections: Fundus, body, cervix.
• Wall Layers: Perimetrium, myometrium, endometrium.
  • Endometrium: Stratum basalis (non-shedding) and stratum functionalis (sheds during menses).

Menstrual Cycle

• Phases: Menses, proliferative, secretory.
• Menses Phase: Shedding of endometrial lining.
• Proliferative Phase: Endometrium rebuilds with rising estrogen.
• Secretory Phase: Endometrium prepares for implantation, influenced by progesterone.

Breast Anatomy

• Accessory organs for lactation.
• Structures: Nipple, areola, lobes with alveoli.
• Hormone response leads to changes during menstrual cycle and pregnancy.

Hormonal Birth Control

• Uses estrogen and progesterone to prevent ovulation.
• Important to follow dosage instructions to prevent pregnancy.

Female Reproductive Aging

• Fertility peaks in twenties, declines more rapidly after 35.
• Menopause: Ends reproductive function, average age 50-52.
• Hormonal changes lead to symptoms like hot flashes, osteoporosis.
• Hormone therapy considered for symptom relief, but debated.

Disorders of the Female Reproductive System

• Cervical Cancer: Often caused by HPV, preventable with vaccination.
• Breast Tissue Response: Swelling and tenderness due to hormonal changes.

These notes summarize the key points from the lecture on the anatomy and physiology of the ovarian reproductive system, covering structures, processes, cycles, and related health topics.