Male Reproductive System

Overview of the Reproductive System

• Overall function: Produce offspring
  • Male:
  • Produce sperm
  • Deliver sperm to female
  • Female:
  • Produce eggs
  • Receive sperm
  • Provide site for fertilization
  • Harbor and nourish fetus
  • Give birth
  • Nourish offspring

Primary Sex Organs

• Function: Produce gametes and supply genetic material from each parent
  • Female: Ovary (produces eggs)
  • Male: Testis (produces sperm)

Secondary Sex Organs

• Function: Support reproductive processes
  • Male: Spermatic ducts, glands, and penis (storage, maintenance, and conveyance of sperm)
  • Female: Uterine tubes, uterus, vagina (unite sperm and egg, harbor fetus, deliver offspring)

Scrotum

• Contains: Testes
• Median septum: Divides scrotum into left and right compartments
• Spermatic cord:
  • Fibrous connective tissue channel containing ductus deferens, neurovasculature, and lymphatics
  • Travels through inguinal canal

Scrotal Temperature Control

• Importance: Sperm production requires a cooler environment
• Cremaster muscle:
  • Continuation of internal oblique muscle
  • Contracts/relaxes to change position of testes
• Dartos fascia:
  • Subcutaneous smooth muscle that holds testes against the body
  • Alters scrotal surface area to conserve/release heat
• Pampiniform plexus:
  • A venous network surrounding the testicular artery acting as a countercurrent heat exchanger

Testes

• Function: Produce sperm and sex hormones
• Tunica vaginalis:
  • Double layer of connective tissue derived from the abdominal peritoneum
• Tunica albuginea:
  • Fibrous capsule that projects into testis, dividing it into lobules

Testicular Lobules

• Components:
  • Interstitial endocrine cells: Produce testosterone
  • Seminiferous tubules: Site of sperm production
  • Germ cells: Develop into sperm with the support of nurse cells (provide nutrients, remove waste, secrete proteins)

Spermatic Ducts

• Efferent ductules:
  • Transmit sperm to epididymis (ciliated)
• Epididymis:
  • Site of sperm maturation and storage; single coiled duct; sperm may remain viable for approximately 60 days
• Ductus deferens:
  • Carries sperm into pelvic cavity; ampulla (terminal portion) empties into ejaculatory duct

Accessory Glands

• Seminal vesicles:
  • Contribute about 60% of seminal fluid (contains glucose, prostaglandins, alkaline compounds)
• Prostate:
  • Contributes about 30% of seminal fluid (contains spermine, prostate-specific antigen)
• Bulbourethral glands:
  • Provides lubrication and neutralizes residual acidity of urine

Common Conditions

Benign Prostatic Hyperplasia (BPH)

• Most common prostate condition affecting 90% of males by age 85
• Symptoms:
  • Increased size of prostate compressing urethra
  • Difficulty initiating/completing urination, potential pain during urination or ejaculation
  • Untreated, may lead to UTIs or kidney damage

Testicular Circulation

• Testicular artery:
  • Very low pressure (no pulse)
• Pampiniform plexus:
  • Merges to form testicular veins (right to inferior vena cava, left to left renal vein)

Blood-Testis Barrier (BTB)

• Definition: Boundary formed by tight junctions between nurse cells
• Function: Protects developing sperm and allows nurse cells to control the extracellular environment

Descent of the Testes

• Process wherein testes develop in abdomen and descend into the scrotum, carried along by the gubernaculum through the inguinal canal

Inguinal Canal and Hernias

• Connection: Between abdominal cavity and external genitalia; can experience hernias where intestines protrude into the canal

Penis Anatomy

• Structure: Divided into root (internal portion), shaft, glans (ends at urethral orifice)
• Shaft Composition:
  • Erectile tissue (trabeculae and lacunae)
  • Contains corpus spongiosum (encloses urethra) and corpora cavernosa (surrounded by tunica albuginea)

Penis Circulation

• Supplied by branches of internal pudendal arteries; drained by various venous plexus

Conclusion

• Recap on the complexity and functionality of the male reproductive system, emphasizing its critical role in reproduction and various potential health challenges that may arise.