Feedback Mechanism in the Female Reproductive System

Introduction

• Previous discussion: Male and female reproductive systems and hormones.
• Current focus: Feedback mechanism in the female reproductive system.

Menstrual Cycle Overview

• Occurs every 28 days, starting between ages 10-13.
• Continues for about 40 years.
• Controlled by hormones, affecting ovum development and uterine changes.
• Monthly cycle involving ovary and uterus changes.

Hormonal Control

• Follicle Stimulating Hormone (FSH)
  • Produced by anterior pituitary gland.
  • Stimulates follicle maturation and estrogen production.
• Estrogen
  • Produced by follicle cells.
  • Signals increased estrogen levels in blood.
• Luteinizing Hormone (LH)
  • Secreted by pituitary gland.
  • Stimulates ovulation.
• Progesterone
  • Produced by corpus luteum.
  • Prepares uterine wall for implantation.

Menstrual Cycle Phases

1. Follicle Stage
   • Ovarian follicle grows to maturity.
2. Ovulation Stage
   • Ripe follicle releases an ovum.
3. Corpus Luteum Stage
   • Uterus prepares for implantation.
4. Menstrual Flow Stage
   • Uterine lining breaks down and is discharged.

Feedback Mechanism

• Negative Feedback
  • High estrogen levels inhibit FSH production.
  • High progesterone levels inhibit LH release.
• Positive Feedback during Labor
  • Oxytocin release causes contractions, leading to more oxytocin release.

Menstrual Cramps

• Caused by uterine wall contractions.
• Excessive prostaglandins cause cramps and inflammation.

Summary of Hormone Functions

• Estrogen
  • Develops female characteristics and thickens endometrium.
• Progesterone
  • Stimulates endometrium and inhibits contractions.
• Luteinizing Hormone
  • Maintains corpus luteum and stimulates ovulation.
• Follicle Stimulating Hormone
  • Stimulates follicle formation.

Conclusion

• Menstrual cycle prepares body for pregnancy.
• Feedback mechanisms regulate hormone levels.

Next Steps

• Future discussion: Nervous system regulation of feedback mechanisms for homeostasis.

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