Testis

The testis is the male gonad. It is homologous with the ovary of the female

General features:

  • Testicle are oval in shape.
  • Measures around 1.5 inches in length, 1 inch in breath and ¾ inch in thickness.
  • Weighs around 10 to 15 grams.
  • Testis is suspended in the scrotum by the spermatic cord. This helps in maintaining the testis temperature 2 degrees lower than body tempertature. Exposure to cold testis are pulled towards the body to keep the testis warm. This mechanism is very helpful in production of sperm.
  • Left testis usually suspended more inferiorly than the right and more porne for varicocele (dilatation of the pampiniform veins plexus).

Follow up:

External features
The testis has

  • Upper pole and lower pole
  • Anterior border and posterior border
  • Medial and lateral surface

Coverings of the testis

  • Outer, tunica vaginalis testis – visceral and parietal layers ( abnormal collection of fluid between these two layers is called hydrocele)
  • Inner, tunica albuginea – tough fibrous coat covering the testis and the fibrous septa extend from capsule to interior of testis and divide it into 200 to 300 lobules

Structure of the testis

  • The testis consists of 200 to 300 lobules.
  • Each lobule contains two to three seminiferous tubules.
  • Each tubule is highly coiled on itself.
  • Seminiferous tubules measures about two feet in length and 0.2 mm in diameter
  • Tubules join together to form 20 to 30 straight tubules
  • Straight tubules anastomose with each other to form rete testis
  • Rete testis are connect to epididymis by efferent ductules


Functions
1.Seminiferous tubule in the testis are lined with a layer of cells which starts production of spermatozoa (sperm) after puberty. Production of sperm is called spermatogenesis and takes 72 days.
2.Leydig cell is a specialized cell present between the seminiferous tubule secretion testosterone (male hormone

Blood Supply
1.Arteries – right and left testicular arteries from abdominal aorta (level of L.V.1)
2.Veins

  • testicular vein – starts as a venous network, pampiniform plexus, which becomes reduced to a single vein as it ascends through the inguinal canal
  • right testicular vein – into inferior vena cava
  • left testicular vein – into left renal artery

Lymphatic Drainage – paraaortic (lumbar nodes) – level of L.V.1

Nerve Supply – autonomic nerves arise as the testicular plexus of nerves on the testicular artery, which contains vagal parasympathetic fibers and sympathetic fibers from T7 segment of spinal cord

Clinical co-relation
Ectopic testis
Hydrocele
varicocele