Corpus: Deferent duct

The deferent duct is a component of the male reproductive tract. It is a tortuous muscular duct, approximately 50 cm long when straightened, with a small star-shaped lumen and a thick three-layered muscular wall. Spermatozoa are transported from the epididymal duct to the ejaculatory duct through peristaltic movements.

2.1. Course

The deferent duct begins as a continuation of the epididymal duct at the epididymis and travels within the spermatic cord through the inguinal canal into the pelvic cavity. It reaches the urinary bladder from the dorsal side, where it expands to form the ampulla of the deferent duct. It then joins the excretory duct of the vesicle gland to form the ejaculatory duct, which opens into the urethra at the seminal colliculus.

Along its course, the deferent duct crosses several key structures:

• Inferior epigastric vessels
• External iliac vessels
• Ureter

2.2. Supply

The three-layered muscular wall of the deferent duct is sympathetically innervated via the inferior hypogastric plexus during ejaculation. Arterial blood is supplied by the artery of the deferent duct, a branch of the non-obliterated part of the umbilical artery. Venous drainage occurs through the pampiniform plexus into the testicular veins, as well as via the vesicoprostatic venous plexus and vesical veins into the internal iliac vein.

Lymphatic drainage of the deferent duct occurs through the internal iliac lymph nodes and partially through the lumbar lymph nodes.

The deferent duct has a three-layered structure:

• The tunica mucosa consists of a two-layered columnar epithelium with stereocilia and numerous longitudinal folds. The lamina propria of the mucosa is minimally developed and contains elastic fibers that connect to the underlying muscular layer.
• In histological section, the muscular layer exhibits a three-layered structure, with an inner and outer longitudinal layer and a middle circular layer of muscle. The muscle cells are arranged in a spiral pattern, allowing for the rapid transport of sperm during ejaculation.
• The adventitia contains connective tissue, along with blood vessels and nerves, providing support and innervation to the deferent duct.

Surgical severing of both deferent ducts results in infertility. This procedure, known as a vasectomy, is commonly performed for permanent sterilization.

A congenital absence of one or both vas deferens is referred to as deferent duct aplasia. This condition is often linked to mutations in the CFTR gene and, when it occurs bilaterally, it leads to infertility.

• Waldeyer et al, Human Anatomy: Textbook and Atlas in One Volume (De Gruyter Studium) (19th totaly rev. ed.), De Gruyter, 2012

• Course script Histology: A guide to microscopic anatomy, Faßbender, Ralf (author); 09/2020 Elsevier Verlag; used with the kind permission of the author