External structure and main landmarks
Anatomically, the gland is oval in shape and characterized by lateral flattening. To correctly orient the organ in space, several key anatomical structures are distinguished.
External landmarks:
- Surfaces: the medial and lateral surfaces are distinguished (facies medialis et lateralis).
- Borders: the organ is bounded by anterior and posterior borders (margo anterior et posterior). It is important to note that the epididymis (epididymis) is located precisely along the posterior border.
- Poles (extremities): the superior and inferior poles are distinguished (extremitas superior et inferior).
Tunics of the organ
Externally, the gland is reliably protected by a system of tunics that ensure the maintenance of its shape and structural integrity.
The primary framework is provided by the tunica albuginea (tunica albuginea testis). Superficial to it lies the tunica vaginalis (tunica vaginalis testis). The latter has a complex structure and consists of two layers forming a closed cavity:
- The visceral layer (lamina visceralis), closely fused with the organ.
- The parietal layer (lamina parietalis), located more superficially.
Internal structure and tubular pathways
The internal structure of the gland has a strictly lobular character. This structure is formed due to connective tissue septa extending from the dense tunica albuginea (tunica albuginea) deep into the organ. They divide the parenchyma into separate areas — testicular lobules (lobuli testis).
Inside each lobule lies a complex pathway system:
- Initially, there are convoluted seminiferous tubules (tubuli seminiferi contorti).
- Gradually, they straighten and transition into straight seminiferous tubules (tubuli seminiferi recti).
- The straight tubules, in turn, merge to form a single rete testis (rete testis).
Briefly: answers to topical questions
Which structure forms the mediastinum testis?
The mediastinum testis (mediastinum testis) is formed by a thickening of the tunica albuginea that projects deeply into the interior of the organ. This structure acts as a kind of central core. From the mediastinum, testicular septa (septula testis) radiate toward the periphery, dividing the parenchyma of the organ into approximately 250 lobules (lobuli testis).
Where do the tubules of the rete testis empty?
The tubules of the rete testis (rete testis) open into the efferent ductules of the testis (ductuli efferentes). From the outer side of the rete testis, 12–15 efferent ductules emerge. Their initial straight segments are located within the testis itself at the exit from the mediastinum, while the main convoluted and longer part forms the head of the epididymis.
By which arteries is the testis supplied with blood?
Blood supply to the testis is provided by the testicular artery (a. testicularis) and the cremasteric artery (a. cremasterica).
Where does venous drainage from the testis occur?
Venous drainage from the testis occurs through the pampiniform plexus (plexus pampiniformis), which then continues into the testicular vein.
- Right testicular vein (v. testicularis dextra) — drains directly into the inferior vena cava (v. cava inferior).
- Left testicular vein (v. testicularis sinistra) — drains into the left renal vein (v. renalis sinistra).
Which tunics directly cover the testicular parenchyma?
The testicular parenchyma is directly covered by the organ's proper tunics, arranged in layers.
- Tunica albuginea (tunica albuginea) — a fibrous capsule enclosing the seminiferous tubules. It lies beneath the visceral layer of the tunica vaginalis.
- Tunica vaginalis testis (tunica vaginalis testis) — covers most of the organ. It has two layers: the visceral layer (lamina visceralis) and the parietal layer (lamina parietalis).
To memorize the sequence of internal pathways: "Convoluted paths always lead to Straight solutions in the Rete" (Convoluted tubules → Straight tubules → Rete testis).
Class and exam questions
Where exactly is the epididymis located?
The epididymis (epididymis) is located strictly along the posterior margin (margo posterior) of the gland.
What layers are distinguished in the tunica vaginalis?
The tunica vaginalis (tunica vaginalis testis) consists of two layers: the visceral and parietal plates (lamina visceralis et parietalis).
How are the testicular lobules formed?
The lobules (lobuli testis) are formed by septa extending inward from the surrounding tunica albuginea.
What else to study on this topic
- Detailed structure of the epididymis
- Histological structure of the convoluted seminiferous tubules
- Topography of the rete testis and its connections
- Features of the formation of the layers of the tunica vaginalis
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