BE PR OD UCTION. 



447 



tubules, and by the constant formation of others behind them are gradually 

 pushed outward along the ducts. 



The Ducts of the Testis. — The ducts of the testis (Fig. 219) comprise a 

 succession of tubes of different morphological and physiological values. 

 They are approximately twenty-five feet in length, and are named, in 

 order, tubuli recti, rete vaseulosum, vasa efferentia, canal of the epididymis, 

 vas deferens, and ejaculatory duct. The tubuli recti (tr) and rete vaseulosum 

 (rv), being mere channels for the 

 passage of spermatozoa, present no 

 special physiological features. The 

 vasa efferentia (ve) and the canal of 

 the epididymis (e) contain smooth mus- 

 cular tissue in their walls, and, more- 

 over, are lined by ciliated epithelium, 

 the cilia causing a movement out- 

 ward ; both of these features doubt- 

 less aid in the outward passage of 

 the spermatozoa. The excretory duct 

 of the testis, or vas deferens (vd), 

 with its offshoot, the seminal vesicle, 

 is more important physiologically. 

 It is nearly two feet in length, with 

 a diameter throughout the greater 

 part of its course of one-tenth of an 

 inch. Near its termination, however, 

 it is larger and sacculated, and re- 

 sembles the seminal vesicle ; it is 

 known here as the ampulla of Henle. 

 Its epithelium is not ciliated, but its 

 walls contain a very thick, plain mus- 

 cular layer consisting of outer longi- 

 tudinal and inner circular fibres. In 

 the walls of the ampulla of Henle 

 exist small tubular glands. The vas 

 deferens is an important storehouse 

 for the spermatozoa. The glands 

 near its termination supply a part of the liquid of the semen. The muscles 

 in its walls, by contracting, aid in the seminal discharges. The seminal 

 vesicle (vs) is a branched diverticulum from the vas deferens. In structure 

 it is not radically unlike the ampulla of Henle, its walls containing muscular 

 layers and glands. An important function is to contribute liquid to the 

 semen. Of all the organs the seminal vesicles contribute probably the 

 greatest share of liquid. Microscopic examination has somewhat weakened 

 the old belief that the vesicles are storehouses for spermatozoa, but Rehfisch ' 

 'Rehlisrli : I)< utxrhe medicinische Wochcmchrift , 1896, xxii. 8. 245. 



Fig. 219.— Diagram of the male productive 

 organs; t, testis; ts, seminiferous tubules; tr, 

 tubuli recti; rv, rete vaseulosum; ve, vasa effer- 

 entia; e, canal of the epididymis; bo, vas aberrans; 

 vd, vd, vas deferens; va, Beminal vesicle: de, ejac- 

 ulatory duct j pr, prostate gland; b, urinary blad- 

 der; en. cuwper's gland; u, urethra; pn, penis. 



