American Urological Association - Epididymis
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Image A

Image B

  • Functions to accumulate and store spermatozoa, during which time the sperm gain motility.
  • Consists of a very long (5-6 meters) highly convoluted single duct extending down the posterior aspect of the testis to the lower pole, where it becomes the ductus deferens (image A).
  • Histology:
    • Tube of smooth muscle lined by pseudostratified ciliated epithelium and basal cells (image B).
    • Single layer of smooth muscle proximally; 3 layers distally.
    • General appearance is "smooth" lined tubules (as opposed to sawtooth border of the efferent ductules).
  • Transit time for sperm: 12 days.