382 



PRACTICAL HISTOLOGY. 



[XXXV. 



Septa. 



Tunica albuginea. 



Cavity of tunica 

 vaginalis. 



Outer layer of tunica 

 vaginalis. 



Vas deferens cut. 

 Spermatic vein. 



FIG. 355. T.S. of Testis. 



their apices towards the corpus Highmori. The tunica albuginea 

 consists of dense fibrous tissue, but it is of looser texture internally, 

 where it has numerous vessels and lymphatics. This inner layer is 



sometimes called the tunica 

 vasculosa, and is continuous 

 with the septa. Each lobule 

 contains 2-8 seminal tubules. 

 These convoluted tubules (800) 

 begin by a blind extremity, 

 and are of considerable length 

 (30-50 cm.) and of nearly 

 uniform diameter (.3 mm. or 

 140 JJL). The tubules of any 

 one compartment unite at 

 acute angles to form a small 



Arteries. Corpus Epididy- 



Highmori mis. number ot much narrower 

 straight tubules (20-25 //,) 

 tubuli recti which pass into 

 the mediastinum and there form a network of inter-communicating 

 tubules of irregular diameter (24-180 //,) rete testis (fig. 356). 



From this proceed 1215 wider 

 ducts vasa efferentia which 

 are straight at first, but some 

 become convoluted and form a 

 series of conical eminences 

 coni vasculosi which together 

 form the head of the epididy- 

 mis. The epididymis, consist- 

 ing of a single convoluted tube 

 (600 cm., or 20 feet long), is 

 continued into a thick-walled 

 muscular tube vas deferens 

 (60 cm., or 2 feet long) which 

 conducts the secretion to the 

 urethra, and is, in fact, the 

 excretory duct of the testis. 



The seminiferous tubules 

 consist of a thick membrane 

 composed of flattened nucleated 

 cells, arranged like membranes 

 and lined internally by a base- 

 ment membrane. The latter is 

 lined by several rows of 



cubical cells, which differ much in appearance, according to 

 the functional activity of the organ. In the resting condition, 



End of con- 

 voluted tube. 



Rete Testis. 



FIG. 356. Convoluted and Straight Tube of 

 Testis. 



