Accessory Male Genital Glands

Accessory Male Genital Glands

• Located along the excretory duct system
• Produce secretions essential for reproductive function in men
• Testosterone is required to maintain their functional activity
• Consist of:
  • Seminal vesicles
  • Prostate
  • Bulbourethral glands

Seminal Vesicles

• Two highly tortuous tubes about 15 cm in length and 5 cm long when coiled
• Adjacent to posterior aspect of bladder
• Formed of 3 layers:
  • Mucosa: pseudostratified columnar non-ciliated epithelium, highly folded for large surface area for secretion
  • Musculosa: inner circular and outer longitudinal smooth muscles
  • Adventitia: loose CT rich in elastic fibers
• Function:
  • Give about 70-80% of the seminal fluid
  • Secretion is viscid, yellowish (lipochrome pigment), rich in fructose, prostaglandins, proteins & fibrinogen
  • Fructose is the main nutrient for spermatozoa and is the source of energy for their motility

Prostate

• Surrounding the neck of the urinary bladder
• Exocrine compound tubulo-alveolar gland
• Formed of stroma and parenchyma
  • Stroma: capsule (thick fibromuscular, rich in blood vessels) and seminiferous tubule
  • Parenchyma: epithelium, BM, myoid cells, Leydig cells
• Function: not specified in the text

Vas Deferens

• Straight muscular tube, starts from tail of epididymis and continues towards the prostate
• Formed of 3 layers:
  • Mucosa: pseudostratified columnar ciliated with stereocilia (in proximal part) → Non-ciliated (in distal part)
  • Musculosa: very thick (palpable & firm) in inguinal canal, with three layers: inner longitudinal, middle circular and outer longitudinal
  • Adventitia: loose CT rich in elastic fibers
• Function:
  • Thick smooth muscle → strong peristaltic contractions → expulsion of the spermatozoa → ejaculatory duct during ejaculation

Spermatic Cord

• Passes through the inguinal canal
• Includes:
  • Vas deferens
  • Pampiniform plexus of veins
  • Testicular artery & vein
  • Nerve fibers & Lymphatics
  • Cremasteric muscle: striated involuntary muscle

Ejaculatory Ducts

• Formed by union of ampulla of vas deferens with the duct of seminal vesicle
• Compress the urethra and usually lead to difficult micturition
• Malignant prostatic carcinoma arises from acini of the peripheral zone

Bulbourethral Glands of Cowper

• Two small compound tubulo-alveolar exocrine gland on the under surface of membranous urethra
• Lined by simple cuboidal epithelium
• Fibromuscular septa divide each gland into lobes
• Secreted mucus → clear and acts as a lubricant

Seminal Fluid (Semen)

• It is the product of ejaculation, consists of spermatozoa and seminal fluid
• Seminal fluid is derived from the seminal vesicles (70%), prostate (25%) and bulbo-urethral gland (5%)
• By the time of ejaculation, spermatozoa have matured and acquired motility; however, they remain incapable of fertilizing an ovum until after undergoing a process called capacitation within the female genital tract

The Penis

• The penis is the male copulatory organ for the deposition of spermatozoa into the female reproductive tract
• Composed of the erectile tissues (numerous endothelial-lined blood spaces that are separated by CT trabeculae and smooth muscle cells)
• Erectile tissue exists in the form of three columns:
  • The two dorsal columns are called the corpora cavernosa and the single ventral column is the corpus spongiosum, through which runs the penile urethra
• Corpora cavernosa are covered by a thick layer of dense CT (Tunica albuginea) while corpus spongiosum is covered by a thin tunica albuginea
• Tunica albuginea is surrounded by fascia penis rich in elastic fibers