1.1 Development

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  The male reproductive tract is developed from the intermediate mesoderm, which forms a urogenital ridge that gives rise to testicular stroma and the mesonephric (Wolffian) duct.

  
  
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  Mesodermal (coelomic) epithelium gives rise to Sertoli cells and the paramesonephric duct.

  
  
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  Primordial germ cells migrate from the yolk sac and give rise to the spermatogonia.

The anatomy of the male reproductive tract is shown in Figure 7.1.

Figure 7.1 Anatomy of the male reproductive tract.

1.2 Scrotum

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  The scrotum is located outside of the abdominal cavity.

  
  
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  It comprises a thin layer of smooth and skeletal muscle and skin.

1.3 Testis

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  The testis contains 200 to 300 lobules, and each lobule contains two to three highly coiled seminiferous tubules.

  
  
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  At puberty, the seminiferous tubules begin to produce about 400 million sperm.

  
  
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  The spermatogenic cells are protected by a blood–testis barrier, which keeps the cells protected from activating the immune system.

1.4 Epididymis

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  Sperm completes maturation and gains the ability to swim and fertilise.

1.5 Ductus Deferens

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  The ductus deferens runs superior to the testicles and enters the abdominopelvic cavity, runs posterior to the bladder, passes by the seminal vesicle, forms the ampulla and ejaculatory duct, and finally leads into the prostatic urethra.

1.6 Clinical Implications

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  In vasectomy, part of the ductus deferens is ligated and excised through an incision in the superior part of the scrotum. Hence, the subsequent ejaculated fluid from the seminal glands, prostate and bulbourethral glands contain no sperm. Any sperm not expelled degenerates in the epididymis and proximal part of the ductus deferens.

  
  
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  Abscesses of the seminal glands may rupture, and pus can enter the peritoneal cavity.

  
  
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  Benign hypertrophy of the prostate is a common cause of urethral obstruction, cystitis and kidney damage.

2.1 Ovaries

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  The ovaries are supported along the lateral pelvic sidewalls by the ovarian ligaments (attaching to the posterolateral aspect of the uterus), the mesovarium (the anastomotic region of the uterine and ovarian vessels), and the infundibulopelvic ligament, which are reflections of the broad ligament attaching the ovaries to the lateral pelvis.

  
  
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  The ovaries rest in the ovarian fossa, immediately adjacent to the iliac vessels and the ureters.

  
  
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  They contain three distinct cell populations:

  
  
  
  
  1. 
     

     ◦ germ cells

     
     
  2. 
     

     ◦ stromal cells, which are tightly packed around developing follicles and which secrete hormones

     
     
  3. 
     

     ◦ epithelium

  
  

2.2 Fallopian Tubes

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  Each fallopian tube is 7–12 cm in length and <1 cm in diameter.

  
  
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  Parts of fallopian tubes (medial to lateral) include:

  
  
  
  
  1. 
     

     ◦ interstitial (narrowest)

     
     
  2. 
     

     ◦ isthmus: 1 mm in diameter; the perfect spot for tubal ligation

     
     
  3. 
     

     ◦ ampulla: 6 mm in diameter; fertilisation of the ovum occurs here, and most ectopic pregnancies occur in the ampulla

     
     
  4. 
     

     ◦ fimbria (infundibulum)

  
  
  
  
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  The fallopian tubes are covered by peritoneum and connected to the upper margin of broad ligament through the mesosalpinx.

  
  
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  Blood supply is by the uterine and ovarian arteries.

  
  
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  They are innervated by the uterovaginal and ovarian plexus.