MAMMALIAN TESTIS 



321 



an accumulation of yellow pigment. By the 

 end of a month, the interstitium becomes 

 invaded by fibroblasts. The tubules, al- 

 though not yet shrunken, show a thickened 

 basement membrane. The necrotic contents 

 conglomerate into a mass. After 7 months, 

 pronounced interstitial fibrosis is present, 

 extending from the periphery toward the 

 center. Plasma cells are seen. Some of the 

 Sertoli cells survive. The tubular debris is 

 removed. Thus, it seems that the Leydig 

 cells are most resistant to arterial occlusion. 

 The Sertoli cells are the next most resistant, 

 followed by the resting spermatogonia. The 

 active differentiating cells are most sus- 

 ceptible to arterial occlusion. 



A different type of lesion is produced by 

 ligation of the superior epididymal artery. 

 Focal necrosis of the initial segment of the 

 caput occurs (Macmillan, 1956; Harrison 

 and Macmillan, 1954). This disrupts the 

 pathway between the vasa efferentia and the 

 ductus epididymidis. The vasa distal to the 

 ligature become choked with sperm within 

 3 days. The testes enlarge and then atrophy. 

 In this manner, permanent atrophy of the 

 testes occurs, with azoospermia due to ob- 

 struction. 



Vn. The Nervous System and 

 the Testis 



It is difficult to see nerve endings in the 

 parenchyma of the testis. Van Campenhout 

 (1947, 1949a, b) described masses of para- 

 ganglionic cells in the midportion of the 

 genital ridge of the testis during develop- 

 ment. The fibers of these cells are inti- 

 mately associated with the interstitial cells. 

 The testes of 22-day-old pigs contain nu- 

 merous neuro-interstitial connections be- 

 tween nerve fibers and groups of Leydig 

 cells in the hilar zone or near the tunica. 



The origin of testicular nerve fibers is 

 not entirely clear. The general belief is that 

 the testis receives fibers from the lumbar 

 sympathetic chain. These nerve fibers in- 

 nervate only the blood vessels in the rat and 

 cat. Varying reports have been made of 

 the nervous connections in man. Apart from 

 vasomotor and sensory nerves, few fibers 

 enter the human testis. These follow the 

 course of the arteries to the septula and 

 make contact with the Leydig cells. Three 

 types of contact are made, namely (1) peri- 



FiG. 5.7. Diagram of arterial supply of rat testis. 

 The testicular artery (a), as it nears the testis, be- 

 comes tortuous just after giving off a branch (c) 

 to the head of the epididymis that also supplies 

 the fatty body (upper right). On reaching the 

 testis, the testicular artery goes to the deep surface 

 of the tunica albuginea. After coursing around the 

 inferior pole, the artery winds up the anterior 

 border of the testis, entering the parenchyma at e 

 to break up into its terminal branches. The vasal 

 artery (6) passes along the vas to reach the tail 

 of the epididymis, where it anastomoses with the 

 descending branch of the artery (d) supplying 

 the body and tail. In the experiments, the tes- 

 ticular artery was permanently interrupted at 

 point X (in the abdomen) or temporarily oc- 

 cluded at point Y. In the former case, the testis 

 still would have some blood supply via the vasal 

 artery, the branch of the testicular artery to the 

 tail, and the terminal part of the testicular artery. 

 However, the testicular artery is an end-artery at 

 point Y. (From A. G. Oettle and R. G. Harrison, 

 J. Path. & Bact., 64, 273, 1952.) 



neural, in which the Leydig cells lie along- 

 side the nerve, (2) intraneural, in which 

 groups of Leydig cells may be found within 

 the perineurium, and (3) interdigitational, 

 in which the course of the nerve breaks a 

 cluster of Leydig cells into small groups 

 (Okkels and Sand, 1940-1941). It is not 

 certain that nerve fibers actually pene- 

 trate Leydig cells (Peters, 1957; Gray, 

 1947). Peters noted that nerve fibrils also 



