Lecture Notes: Male Reproductive System and Semen Composition

Key Components of Semen

• Sources:
  • Seminal Vesicles
  • Prostate
  • Bulbourethral Glands (also known as Cowper's Glands)

Bulbourethral Glands (Cowper's Glands)

• Secretes: Alkaline mucus
• Function:
  • Neutralizes acidity in the male urethra and vaginal tract, which is typically acidic due to urine and to protect against pathogens.
  • Alkalinity helps sperm survive by neutralizing these acidic environments.

Structure of Sperm

• Head
  • Contains 23 chromosomes
  • Has an acrosome cap with enzymes to penetrate the egg
• Midpiece
  • Contains mitochondria for energy
• Flagellum
  • Facilitates movement

Seminal Vesicles

• Secretes:
  • Fructose: Energy source for sperm
  • Prostaglandins:
    • Help sperm navigate through the female reproductive system
    • Cause uterine contractions to assist sperm movement
  • Semenogelin:
    • Causes semen to coagulate post-ejaculation (5 minutes)
    • Masks sperm from the female immune system temporarily

Prostate

• Secretes:
  • Digestive Enzymes:
    • Break down coagulated semen (e.g., pepsinogen, proteases, amylase, PSA)
  • PSA (Prostate Specific Antigen):
    • Digestive role, also used to detect prostate enlargement or cancer
  • Lysozyme: Antibacterial enzyme
• Energy Sources:
  • Citric Acid: Utilized in the Krebs cycle for ATP production
  • Acid Phosphatase:

pH and Environment

• Semen pH: Generally alkaline due to secretions from seminal vesicles and bulbourethral glands
• Prostatic Secretions: Slightly acidic due to citric acid and acid phosphatase

Important Concepts

• Neutralization of acidity: Essential for sperm survival
• Sperm motility and energy: Provided by fructose and citric acid
• Prostaglandins role: Facilitate sperm transport
• Coagulation and immune evasion: Temporary protection for sperm in female tract

Clinical Relevance

• PSA Levels:
  • Indicator for prostate health
  • High levels may suggest prostate enlargement or cancer

Conclusion

• Ensure understanding of the roles of each gland and secretion in semen production
• Review the structure and function of sperm cells
• Emphasize the importance of pH balance and nutrient provision for sperm viability