Notes
Testes and Spermatic Cord
Testes
- The primary sex organs of the male; they produce sperm and hormones.
- Their anatomical position "outside" of the body reflects a physiologic necessity: spermatogenesis (formation of sperm) requires a temperature slightly lower than that of the body.
Tunica albuginea
- Fibrous outer surface of the testis
Mediastinum of the testis
- Where the tunica albuginea forms a thickened ridge along the posterior aspect.
- Septa extend from the mediastinum, which separate the lobules.
Seminiferous tubules
- Lie within the lobules
- Sites of sperm production.
- Specialized cells within the lobules produce hormones that support sperm maturation.
Straight tubules
- Transport sperm from the seminiferous tubules to the rete testis
Rete testis
- Comprises a network of tubules within the mediastinum of the testis.
Efferent ductules
- Converge to deliver sperm to the epididymis
Epididymis
- Stores developing sperm
- Head comprises the tightly coiled merger of the efferent ductules
- Body comprises a singular long coiled duct
- Tail of the epididymis is continuous with ductus deferens
Ductus deferens
- Transports sperm to ejaculatory duct
Tunica vaginalis
- Double-layered sac that comprises a visceral layer, which is closely adhered to the tunica albuginea of the testis, and, a parietal layer, which is in contact with the innermost layer of the scrotum and spermatic cord.
- The cavity of the tunica vaginalis is the space between these two layers, and contains a small amount of fluid, which allows for movement of the testicles within the scrotum.
Spermatic cord
- Passes through the inguinal canal, which is an oblique passageway in the anterior abdominal wall.
- Comprises blood vessels, nerves, the ductus deferens, and several layers of tissue that collectively suspend the testes within the scrotum.
- Prior to testicular descent, the spermatic cord develops as an outpocket of the anterior abdominal wall; thus, its three coverings are derived from the fascial layers of the anterior abdominal wall.
Spermatic Cord Layers:
- Internal spermatic fascia, which is derived from the transversalis fascia of the anterior abdominal wall.
- Cremasteric fascia with muscle fibers, which is derived from the internal oblique fascia and muscle.
- External spermatic fascia, which is derived from the external oblique fascia/aponeurosis.
Scrotum
- A cutaneous sac that holds the testes.
- Dartos fascia and muscle is the inner layer, gives rise to scrotal septum, which separates testes within scrotum.
- Skin is outermost layer of scrotum.
The dartos muscle contracts when cold to wrinkle and thicken the skin, which helps to reduce heat loss.
Clinical correlation:
Torsion of the spermatic cord (aka, testicular torsion) can disrupt blood supply to the testis and cause necrosis; twisting can occur because of defects in the supporting connective tissues.