1942 



HUMAN ANATOMY. 



Fig 1651. 



2042). The testis is of a whitish color, and, although readily yielding, imparts a 

 characteristic impression of resilience when compressed between the fingers. 



Architecture of the Testis. — The framework of the testicle proper consists 

 of a stout capsule, the tunica albiiginea, a dense fibro-elastic envelope from .4-6 mm. 

 in thickness, that gives form to the organ and protects the subjacent soft glandular 

 tissue. Along the posterior border of the testis the capsule is greatly thickened 

 and projects forward as the mediastinum testis or corpus Highmori, a wedge-shaped 

 body (from 2.5-3 cm. in length), from which radiate a number of membranous septa 

 that pass to the inner surface of the tunica albuginea. In this manner the space 

 within the capsule is subdivided into pyramidal compartments, the bases of which lie 

 at the periphery and the apices at the mediastinum. These spaces contain from 150 

 to 200 pyriform masses of glandular tissue, more or less completely separated from 

 one another, that correspond to lobules (lobuli testis). Each of the latter is made up 

 of from one to three greatly convoluted seminiferous tubules, held together by delicate 

 vascular intertubular connective tissue. 



The seminiferoiis tubules — from.15— . 25 mm. in diameter and from 25-70 cm. 

 (10-28 in.) in length — begin as blind canals, wlfich are moderately branched and 



very tortuous ( tubuli conto?-ti) throughout their 

 course until they converge at the apex of the 

 lobule, where they pass over, either directly 

 or after junction with another canal, into the 

 narrow, straight tubules ( tubuli recti) that 

 enter the mediastinum and unite into a close 

 net- work, the 7'ete testis. The latter extends 

 almost the entire length of the mediastinum, 

 and consists of a system of irregular inter- 

 communicating channels, the cuboid epithelial 

 lining of which rests directly upon the en- 

 sheathing fibrous tissue of the mediastinum. 

 With these passages the canals of the testicle 

 proper end, the immediate continuation of the 

 spermatic tract being formed by from fifteen 

 to twenty tubules, the ductuli efferentes, that 

 pierce the tunica albuginea along the posterior 

 border and near the upper pole of the testis 

 and, forming the coni vasculosi, connect the 

 sexual gland with the tube of the epididymis. 

 Structure. — In contrast to the dense 

 fibro-elastic tissue that composes the frame- 

 work of the testis, — the capsule, mediastinum, and interlobular septa, — the con- 

 nective tissue occupying the spaces between the seminiferous tubules is loose in 

 texture and arrangement, consisting of delicate bundles of white fibrous tissue in 

 which elastic fibres are few or absent. In addition to the plate-like cells, leucocytes, 

 and eosinophiles that occur in varying numbers within the meshes of this tissue in 

 conjunction with blood-vessels and nerves, groups or cord-like masses of peculiar 

 polygonal elements, the interstitial cells, also occupy the intertubular stroma, especi- 

 ally in the vicinity of the mediastinum. These cells (Fig. 1654"), from .015-020 

 mm. in diameter, possess relati\ely small round or oval eccentrically placed nuclei 

 and a finely granular protoplasm that usually contains numerous brownish droplets, 

 pigment particles, and, sometimes, crystalloid bodies in the form of minute needles 

 or rods. In some animals, notably in the hog, the deeply colored interstitial cells 

 form conspicuous tracts that impart a dark tint to the testicle in section. Their sig- 

 nificance is uncertain, but there is reason to regard these cells as concerned in internal 

 secretion, producing a specific substance. 



The wall of the convoluted seminiferous tubules consists of a delicate tunica 

 propria, composed of an inner elastic lamella strengthened externally by circularly 

 disposed fibres, within which are several layers of epithelial cells. The latter vary 

 not only before and after the attainment of sexual maturity, but subsequently with 

 functional activity or rest ; in man, howe\er, the variations depending upon these 



Globus major of epididymis 

 ./ 



-Vas deferens 



Coni 

 vasculosi 

 Ductus 

 epididymidis 

 Ductuli 

 efferentes 

 — Tubuli recti 



Rete testis in 

 mediastinum 

 Tubuli 

 contort! 



\'as aberrans 



Ductus 

 epididymidis 

 - Globus minor' 



Septum Tunica albuginea 



Diagram showing relations of secretory 

 tubules and system of ducts. 



