Lesson 4-The Male and Female Reproductive System

The Human Reproductive System

  • Definition: A collection of organs and a network of hormone production that enables organisms to produce offspring.

Male vs. Female Anatomy

  • Identifying Parts: Determine whether anatomical structures belong to the male or female reproductive systems.

Male Reproductive Structures

  • Bulbourethral Gland: Also known as Cowper's gland, excretes a mucous-alkaline secretion in the urethra before ejaculation.

  • Seminal Vesicles: Produce alkaline fluid that mixes with sperm to protect it from acidity and provide energy (fructose).

  • Prostate Gland: Secretes an alkaline fluid, enriched in zinc, contributing to semen's alkalinity.

  • Vas Deferens: Sperm duct that transports sperm from the epididymis.

  • Epididymis: Coiled tube where sperm mature and are stored.

  • Testicles: Produce sperm and testosterone, contain seminiferous tubules for sperm manufacture.

  • Penis: External organ for urination and sexual intercourse; contains the glans at the tip.

  • Scrotum: Pouch of skin that houses testicles, regulates temperature for optimal sperm production.

Female Reproductive Structures

  • Fallopian Tubes: Transport egg from ovary, site of fertilization.

  • Cervix: Connects uterus to vagina, expands during childbirth.

  • Ovary: Produces ova and hormones, contains follicles with eggs.

  • Uterus: Hollow muscular organ; nurtures fertilized egg, menstruation.

  • Vagina: Muscular tube for copulation, passage for menstruation and childbirth.

Importance of the Reproductive System

  • One of the most critical systems for species survival.

  • Functions begin at puberty and substantially differ between sexes.

  • Male reproductive system delivers sperm, while the female nurtures the developing fetus.

Menstrual Cycle Overview

  • Phases: Menstruation, Follicular phase, Ovulatory phase, Luteal phase.

    • Menstruation: Shedding of the uterine lining, lasting 3-7 days.

    • Follicular Phase: Begins at period onset; estrogen rises, thicken the endometrium.

    • Ovulatory Phase: Mature egg released into fallopian tube; lifespan of the egg ~ 24 hours.

    • Luteal Phase: Formation of corpus luteum, secretion of progesterone, prepares endometrium for potential implantation.

Developmental Aspects

  • Human embryos are identical in the early stages and differentiate around the seventh week based on hormone production (androgens in males and estrogens in females).

Additional Information

  • Semen vs. Sperm: Semen comprises 90-95% fluids and nutrients; sperm constitutes only 5-10% of the volume in an ejaculation.