. Text-book of normal histology: including an account of the development of the tissues and of the organs. ■■ -:::■■:./ ■■■■■ :.-.^^Section of human testicle, including portion of tunica albuginea, ex-hibiting general arrangement and structure of tubules : a, tunica albu-ginea ; />, seminiferous tubules cut in various directions ; c, basement-membrane; ^.secreting cells ; e, groups of interstitial cells ;/, intertubularconcective tissue. globus major, which represents the sum of the tortuous coni vas-culosi. These last-named canals unite to form the main tube ofthe epididymis, which is suff
. Text-book of normal histology: including an account of the development of the tissues and of the organs. ■■ -:::■■:./ ■■■■■ :.-.^^Section of human testicle, including portion of tunica albuginea, ex-hibiting general arrangement and structure of tubules : a, tunica albu-ginea ; />, seminiferous tubules cut in various directions ; c, basement-membrane; ^.secreting cells ; e, groups of interstitial cells ;/, intertubularconcective tissue. globus major, which represents the sum of the tortuous coni vas-culosi. These last-named canals unite to form the main tube ofthe epididymis, which is sufficiently convoluted to include itsentire length of twenty feet within the inconsiderable bulk of theepididymis. The seminiferous tubules, 130-140 ii in diameter, possess walls,which are composed of several layers of flattened endothelioid con-nective-tissue plates, applied to which a thin basement-membrane THE MALE REPRODUCTIVE ORGANS. 209 Fig. exists ; inside the latter lies the lining of epithelial cells. The pre-cise character of the cells within the tubule depends upon thecondition of functionalactivity of the organ ; thenotable differences distin-guishing the elements with-in the resting gland fromthose found in the activeorgan depend largely uponthe infrequency within theformer, and the almost uni-versal presence within thelatter, of cells actively en-gaged in karyomitotic divis-ion. The different tubules,however, exhibit great vari-ation in the exact stageof these changes, adjacentcanals, and, in fact, parts ofthe same one, often present-ing the extremes of thecycle side by side. Next the basement-membrane of the seminiferous tubule lies a layer of low cuboidalnucleated parietal cells; this peripheral zone contains cells oftwo kinds: (i) the sustentacular cells, or Sertolis columns,which take no part in the formationof the generative elements, and (2)the spermatogenic cells, which pro-duce elements intimately related
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