EPIDIDYMIS 



341 



Cubical cells. Columnar cells. 



may appear in vesicular masses on the surface of the cells. Often the tall 

 cells, and occasionally the short ones, are ciliated. The cilia vibrate so as 

 to produce a current toward the ductus epididymidis. The epithelium 

 rests on a striated basement membrane which is surrounded by a layer of 

 circular smooth muscle fibers, several cells thick. The muscle layer is 

 thickest toward the ductus 

 epididymidis. Among the 

 muscle cells there are elas- 

 tic fibers, which, like those 

 of the ductus epididymidis 

 and ductus deferens, first 

 appear at puberty. There 

 are no glands in the effer- 

 ent ducts, but the irregu- 

 larities in the epithelium 

 are thought to be due to 

 glandular activity. Before 

 puberty and in old age these irregularities are slight. 



Smooth muscle fibers. Connective tissue. 



FIG. 341. TRANSVERSE SECTION OF A DUCTULUS EFFERENS, 



FROM THE TESTIS OF AN ADULT MAN. 

 The right-band end of the illustration is schematic. No cilia 



could be seen, although those of the epithelium of the epi- 



didymis were well preserved. X 360. 



The ductus epididymidis consists of a two-rowed epithelium with 

 rounded basal cells and tall outer columnar cells. The latter contain 

 secretory granules and sometimes pigment, and have in the middle of 

 their upper surfaces long non-motile hairs, which in sections are usually 

 matted in conical processes (Fig. 41, &, p. 51). The epithelium may 

 contain round cavities opening into the lumen or forming closed cysts. 

 The delicate membrana propria and thick circular muscle layer complete 

 the wall of the ductus, the convolutions of which occur in a loose connec- 

 tive tissue. Toward the ductus deferens the muscle layer thickens. 



There are no glands in the 



ductus epididymidis, but its cells 

 produce considerable secretion 

 in which the spermatozoa be- 

 come active. 



The blood vessels of the epi- 

 didymis, which are few in com- 

 parison with those of the testis, 

 lie in part so close to the efferent 

 ducts as to cause the membrana 

 propria to bulge toward the epithelium. The nerves, besides perivas- 

 cular nets, form a thick plexus myospermaticus provided with sym- 

 pathetic ganglia. It is found in the muscle layer, which it supplies, 

 sending fibers also into the mucosa. In the ductus deferens and seminal 

 vesicles this plexus is said to be more highly developed than in the 

 epididymis. 



" Epithelium. 



Membrana 

 propria. 



Circular layer of 

 muscle fibers. 



Loose connective 

 tissue. 



FIG. 342. TRANSVERSE SECTION OF A HUMAN DUCTUS 

 EPIDIDYMIDIS. X So. 



