Human Anatomy, Part 1 - K. A. Dyubenko, A. K. Kolomiysev, Yu. B. Chaikovsky 2002

Special Part
Reproductive Systems, systemata genitalia — Male Reproductive System, systema masculinum
Internal Male Genital Organs, organa genitalia masculina interna — Structure of the Testis

The Testis proper is covered by a dense fibrous capsule, the tunica albuginea, which thickens at its posterior border to form the Mediastinum testis. From the mediastinum, Connective Tissue septa, known as the septula testis, extend into the interior, dividing the gland into 250–300 lobules, the lobuli testis (Fig. 318 B). Each lobule contains 1–2 convoluted seminiferous tubules, the tubuli seminiferi contorti, which can reach up to 80 mm in length. Near the apex of the lobule, the convoluted tubules straighten into the tubuli seminiferi recti and penetrate the mediastinum testis, forming 18–22 ductuli efferentes testis that empty into the Epididymis. The straight tubules form a network within the mediastinum known as the rete testis. The testis performs two main Functions: a germinative function, aimed at The production of spermatozoa (Male Germ Cells), and an endocrine function, responsible for the synthesis of Sex Hormones (testosterone, estrogens, inhibin, and other androgenic Steroids). The germinative function takes place within the convoluted seminiferous tubules, which make up the bulk of the testicular parenchyma. The endocrine function is carried out by the endocrinocytes of the interstitial tissue, also known as interstitial gland cells or Leydig cells.