Lecture Notes on the Reproductive System

Overview

• Focus on structures, functions, and relationship between reproductive and endocrine systems.
• Important hormones: briefly discussed in previous sessions, revisited due to complexity.
• New content in TEAS 7: female reproductive system, fetal development, and enhanced descriptions of hormonal interactions.

Female Reproductive System

• New Structures: Libya minora, Libya majora, clitoris
  • Part of external genitalia.
  • Possible inclusion in multiple choice questions.
• Key Structures:
  • Ovaries: Egg production.
  • Fallopian Tubes: Site of fertilization.
  • Uterus: Site of embryo implantation and development.
  • Cervix: Opening of the uterus.
  • Vagina: Part of the birth canal.

Fetal Development

• Fertilization:
  • Fusion of egg and sperm, forming a zygote with 46 chromosomes.
• Cell Division:
  • Zygote rapidly divides (mitosis) into a blastocyst, a ball of cells.
• Implantation:
  • Blastocyst implants into uterine wall.
• Embryo Development:
  • Formation of placenta for nutrient and waste exchange.
• Birth:
  • After ~40 weeks, uterine contractions expel the fetus.

Puberty and Hormonal Regulation

• Gonadotropin-releasing Hormone (GnRH): Secreted by the hypothalamus.
  • Stimulates release of FSH and LH from the pituitary gland.
• In Males:
  • LH prompts testosterone production by testes.
  • Testosterone and FSH stimulate spermatogenesis.
• In Females:
  • FSH encourages estrogen production by ovaries.
  • Estrogen matures eggs; surge in LH triggers ovulation.
  • Corpus Luteum: Produced post-ovulation, secretes progesterone to prepare uterus for implantation.

Secondary Sexual Characteristics

• Testosterone in Males:
  • Increases body hair, deepens voice, promotes muscle growth.
• Estrogen in Females:
  • Breast enlargement, pelvis changes, onset of menstruation.

Gamete Production Differences

• Sperm: Constant daily production in testes.
• Eggs: Cyclical monthly release from ovaries.

Practice Questions

• Question 1: Order of events in fetal development:
  • Fertilization → Rapid Mitosis → Blastocyst → Implantation → Placenta Formation → Birth
• Question 2: Effects of LH in males:
  • Promotes testosterone production → Influences sperm production and secondary sexual characteristics.

Key Takeaways

• Understanding the structures and functions of the reproductive system is crucial.
• Relationships between reproductive and endocrine systems significantly influence development processes.
• Familiarity with secondary characteristics and gamete production is essential for mastering the subject matter.