Reproductive System Overview

Key Concepts

• Gonads: Organs that produce gametes and hormones in both males and females.
  • Males: Testes produce sperm and testosterone.
  • Females: Ovaries produce eggs and estrogen/progesterone.
• Duct Systems: Transport gametes in both sexes.
• Accessory Structures/Glands: Secrete fluids into the ducts.
• External Genitalia: Visible differences between males and females.

Male Reproductive System

Gametes Production

• Sperm Production: Males produce about half a billion sperm per day.
• Testes:
  • Synthesize male hormones (androgens, primarily testosterone).
  • Produce sperm (spermatozoa).

Path of Sperm

1. Testes: Production begins in seminiferous tubules.
2. Epididymis: Sperm mature and are stored.
3. Vas Deferens: Transports sperm to ejaculatory duct.
4. Ejaculatory Duct: Mixes sperm with seminal fluid.
5. Urethra: Expels sperm and semen during ejaculation.

Accessory Glands

• Seminal Vesicles: Produce seminal fluid, initiating capacitation.
• Prostate Gland: Contributes to seminal fluid.
• Bulbourethral Glands: Secrete alkaline mucus to neutralize urethra acidity and lubricate.

External Genitalia

• Penis: Contains erectile tissue, vital for copulation.
• Scrotum: Houses testes, regulates temperature for sperm development.

Hormonal Regulation

• Hypothalamus & Anterior Pituitary: Release GnRH, LH, and FSH, regulating testosterone and sperm production.
• Testosterone: Affects CNS, muscle/bone development, secondary sexual characteristics.
• Inhibin: Provides feedback to control sperm production.

Spermatogenesis

• Stages:
  1. Spermatogonia: Stem cells divide by mitosis.
  2. Primary Spermatocytes: Begin meiosis.
  3. Secondary Spermatocytes: Result of meiosis I.
  4. Spermatids: Result of meiosis II, differentiate into sperm.
  5. Spermatozoa: Mature, functionally capable sperm.

Female Reproductive System (Brief Overview)

• Gamete Production: Females produce one gamete (egg) per month, nurturing a developing embryo if fertilization occurs.
• Anatomy includes ovaries, uterine tubes (fallopian tubes), uterus, and vagina.

Developmental Differences

• Male Development: Y chromosome and hormones like Müllerian inhibiting factor steer development from female default to male reproductive structures.
• Testes Descent: Testes descend into scrotum during fetal development, crucial for fertility and health.

This overview covers the male reproductive system's anatomy, function, and hormonal regulation, highlighting distinct processes like spermatogenesis and ejaculatory mechanics, while briefly touching on female reproductive aspects for context.