332 



HISTOLOGY 



TESTIS. 



Septa, Vessels, and Nerves. The general arrangement of the parts of 

 the testis, as they appear in cross section, is shown in Fig. 330. From 

 the tunica albuginea, small connective tissue septa (septula testis} pass to 

 the mediastinum, dividing the testis into "100-200" pyramidal lobules 

 with their apices toward the rete. The tunica albuginea is a dense con- 

 nective tissue layer, containing numerous elastic fibers which increase in 

 abundance with age. Its outer surface is covered with the visceral layer 

 of the tunica vaginalis. The inner portion of the albuginea is very vascu- 

 lar, forming a distinct layer at birth (the tunica vasculosa) . 



Ductus deferens. 

 Blood vessels. 



Epididymis. 



Mediastinum, 



containing the 



rete testis. 



Straight tubules. 



Tunica 

 vasculosa. 



Tunica 

 albuginea. 



FIG. 330. CROSS SECTION OF THE TESTIS OF A CHILD AT BIRTH. X 10. 



Connective tissue extends from the septula among the convoluted 

 tubules. Immediately surrounding them there is a delicate basement 

 membrane, followed by a layer of closely interwoven elastic fibers and 

 flat cells. In the looser connective tissue between the tubules, there are 

 clumps of interstitial cells (Figs. 331 and 335), which arise from mesenchy- 

 mal cells of the genital ridge. Sometimes they retain protoplasmic proc- 

 esses, but more often they are rounded or polygonal structures in close 

 contact, and without distinct cell boundaries. In their abundant proto- 

 plasm there are pigment and other granules, fat droplets, and rod-shaped 



