A. General features. The testes are surrounded by a thick connective tissue layer, the tunica albuginea. They are further surrounded incompletely-medially, anteriorly, and laterally, but not posteriorly—by a sac of peritoneum called the tunica vaginalis. The testes contain the seminiferous tubules, straight tubules, rete testes, and efferent ductules. Arterial blood is supplied from the abdominal aorta via the testicular arteries. A rich collateral arterial blood supply is provided from the internal iliac artery via the artery of the ductus deferens, the inferior epigastric artery via the cremasteric artery, and the femoral artery via the external pudendal artery. The collateral circulation is sufficient to permit ligation of the testicular artery during surgery. Venous drainage is to the right testicular vein, which empties into the inferior vena cava, and the left testicular vein, which empties into the left renal vein. The testicular veins are formed by the union of the veins of the pampiniform plexus. A left-sided testicular varicocele may indicate occlusion of the left testicular vein or the left renal vein by a malignant tumor of the kidney. Lymphatic drainage of the testes is to deep lumbar nodes near the renal hilus; knowledge of this route aids in evaluating the spread of testicular cancer. Lymphatic drainage of the scrotum is to superficial inguinal nodes.
B. Clinical considerations 1. Disorders a. Cryptorchidism results when the testes begin to descend along the noiincil pathway, but do not reach the scrotum. In contrast, an ectopic testis descends along an abnonnal pathway. In cryptorchidism, the undescended testis usually is found within the inguinal canal or the abdominal cavity near the deep inguinal ring. Bilateral cryptorchidism results in sterility because the testes require the cooler temperature of the scrotal sac for spermatogenesis. Cryptorchidism is associated with an increased incidence of cancer and torsion.
b. Hydrocele of the testes occurs when a small patency of the processus vaginalis remains, allowing peritoneal fluid to flow into the tunica vaginalis surrounding the testes.
Figure 15-1. (A) The male reproductive system. Note the pathway followed by sperm: seminifer- ^ ous tubules -> straight tubules rete testes ► efferent ductules > epididymis ► ductus deferens -> ejaculatory duct ► prostatic urethra > membranous urethra > penile urethra. 1 = ureter; 2 = seminal vesicle; 3 = prostate gland; 4 = membranous urethra (with urogenital diaphragm); 5 = bulbourethral (Cowper) glands; 6 = bulb of the penis; 7 = left and right crura of the penis; 8 = epididymis; 9 = testes; 10 = urinary bladder; 11 = apex of the urinary bladder; 12 = ductus deferens; 13 = corpus cavernosum; 14 = corpus spongiosum; 15 = glans penis. (B) Cross-sec-tion of the penis. (A reprinted with permission from Rohen JW, Yokochi C, Lutjen-Drecoll E: Color Atlas of Anatomy, 4th ed. Baltimore, Williams & Wilkins, 1998, p 316; B adapted with permission from Chung KW: BRS Gross Anatomy, 2nd ed. Baltimore, Williams & Wilkins, 1991.)
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A Beginner's Guide to Healthy Pregnancy. If you suspect, or know, that you are pregnant, we ho pe you have already visited your doctor. Presuming that you have confirmed your suspicions and that this is your first child, or that you wish to take better care of yourself d uring pregnancy than you did during your other pregnancies; you have come to the right place.