Female Reproductive System - Hormonal Regulation

Introduction

• Focus on hormones regulating the ovarian cycle.

Hormonal Control

• Hypothalamus:
  • Secretes GnRH (gonadotropin-releasing hormone).
  • Targets the anterior pituitary.
• Anterior Pituitary:
  • Releases FSH (follicle-stimulating hormone) and LH (luteinizing hormone).
  • FSH and LH influence follicle growth in ovaries.

Follicle Development

• Pre-antral Follicle:
  • FSH stimulates local molecular signals.
• Hormonal Secretion:
  • Follicles secrete estrogen, progesterone, and inhibin.
  • Estrogen and inhibin provide negative feedback to hypothalamus and pituitary to regulate follicle development.

Follicular Phase

• Purpose:
  • Select and develop one follicle per cycle.
• Negative Feedback:
  • Prevents multiple ovulations.

Ovulation and Feedback Loop

• Day 12-14:
  • Estrogen levels rise, shifting to positive feedback.
  • Surge in LH leads to ovulation (day 14).
• LH Surge:
  • Necessary for ovulation.

Post-Ovulation

• Corpus Luteum:
  • Forms post-ovulation.
  • Secretes progesterone and estrogen.
  • Maintains negative feedback to hypothalamus and pituitary.

Menstrual Cycle Overview

1. Menstrual Phase (Days 1-5):
   • Shedding of the uterine lining.
2. Proliferative Phase (Days 6-14):
   • Rebuilding of the uterine lining.
3. Secretory Phase (Days 15-28):
   • Glandular and vascular proliferation in the endometrium.

Fertilization and Early Pregnancy

• Fertilization:
  • Occurs in the uterine tube.
  • Implantation in the uterine lining.
• HCG Role:
  • Secreted post-implantation.
  • Maintains corpus luteum and progesterone secretion.

Endometriosis

• Condition:
  • Growth of endometrial tissue outside the uterus.
  • Causes pain and potential infertility.

Uterine and Cervical Health

• Ovarian Cancer:
  • Regular screenings recommended.
• Cervical Cancer:
  • Linked to HPV infection.
  • Preventable with HPV vaccine.

Uterine Structure

• Layers:
  • Perimetrium, Myometrium, Endometrium (functional and basal layers).

Memory Glands

• Function:
  • Lactation (milk production and ejection).
• Hormonal Control:
  • Prolactin stimulates milk production.
  • Oxytocin triggers milk ejection.

Contraception and Cancer

• Contraceptive Methods:
  • Various methods to prevent pregnancy.
• Breast Cancer:
  • Awareness and regular check-ups recommended.

Note: These notes provide a structured overview of hormonal regulation in the female reproductive system, focusing on the ovarian cycle, feedback mechanisms, and associated health topics. Use this as a guide for understanding the complex interactions within the reproductive cycle.