Lecture Notes: Reproductive Systems

General Information

• Turn in handwritten notes for the last lecture on Friday after the lecture.

Female Reproductive System

External Genitalia (Vulva)

• Mons Pubis
  • Superficial fat pad over the pubic symphysis.
• Labia Majora
  • Large lips, folds of skin with fat, muscle, glands, and connective tissue.
  • Contains hair.
• Clitoris
  • Two erectile bodies forming a single projection.
  • Increases in size with stimulation.
  • Homologous to the male penis but without a urethra.
• Labia Minora
  • Folds of skin with glands, no hair.
  • Protects the clitoris, urethra, and vagina.

Breasts

• Extend over the 2nd to 6th ribs.
• Attached to fascia of pectoralis major muscle.
• Comprised of connective tissue forming lobes with secretory glands.
• Alveoli (alveolar cells) form duct systems converging at the nipple.
• Size and shape determined by fat, not glandular material.

Male Reproductive System

Primary Sex Organ

• Testis
  • Plural: testes.
  • Located in the scrotum, a skin pouch.
  • Functions: form sperm and produce testosterone.
  • Prefer a temperature cooler than body temperature (95.6°F).
  • Cremasteric muscle raises the testis to body wall if too cold.

Testis Structure

• Stem Cells
  • Formed in the embryo by the yolk sac.
• Seminiferous Tubules
  • Form sperm from stem cells (spermatogenesis).
  • Contain germinal epithelium with developing sperm.
• Sertoli Cells
  • Supply nutrients, maintain hormonal levels, form blood-testis barrier.
  • Phagocytize cast-off cytoplasm from developing sperm.

Sperm Structure

• Head
  • Contains the nucleus with 23 chromosomes.
  • Acrosome contains enzyme for penetrating the ovum.
• Body
  • Contains mitochondria for energy.
• Tail
  • Propels the sperm.

Hormonal Regulation

• Seminiferous Tubules
  • Stimulated by FSH to produce sperm and Sertoli cells.
• Interstitial Cells
  • Stimulated by LH to produce testosterone.

Duct Systems

• Epididymis
  • Stores and matures sperm.
  • 20 feet long, coiled structure.
• Vas Deferens
  • Muscular tube (~18 inches) for sperm transport during ejaculation.
• Ejaculatory Duct
  • Formed by union of vas deferens and seminal vesicle duct.
  • Enters the urethra through the prostate.

Glands

• Seminal Vesicles
  • Produce ~60% of semen, contain fructose for nourishing sperm.
• Prostate Gland
  • Produces 15-30% of semen, acid secretion activates sperm.
  • Walnut-sized.
• Bulbourethral Glands
  • Neutralize acid in the urethra.

Semen Composition

• Consists of sperm and glandular secretions.
• Ejaculation volume: 2.5 - 6 cc's.

• Visuals & Illustrations

  • Cross-sections of seminiferous tubules, epididymis, vas deferens, and penis were shown.

• Closing Remarks

  • Next session will cover any remaining topics and review for better retention.