Sechenov School
Home › Human Anatomy › Vas Deferens and Seminal Vesicles

Vas Deferens and Seminal Vesicles

Ductus deferens, Vesiculae seminales

For medical students2 min readUpdated 2026-10-10

The vas deferens (ductus deferens) and seminal vesicles (vesiculae seminales) are key paired structures of the male reproductive system. The tubular vas deferens ensures the targeted transport of germ cells, while the glandular seminal vesicles produce fluid secretions that constitute the main liquid component of semen.

Length of ductUp to 50 centimeters from the epididymis
Wall layersMucosa, muscular layer, and adventitia
Topography of vesiclesLocated strictly posterior to the urinary bladder
Function of vesiclesSynthesis of seminal fluid secretions

General Characteristics and Parts of the Vas Deferens

The vas deferens (ductus deferens) is a paired tubular organ of significant length, reaching up to 50 centimeters. It originates directly from the tail of the epididymis and extends toward the formation site of the ejaculatory duct.

For anatomical study and topographic description, the vas deferens is traditionally divided into four sequential parts:

Wall Structure and the Ampulla of the Duct

The pelvic part of the vas deferens features a prominent spindle-shaped dilation known as the ampulla of the vas deferens (ampulla ductus deferentis).

The histological structure of the vas deferens wall is specialized for its transport function. The thick wall consists of three distinct layers:

  1. The inner layer is the mucosa.
  2. The middle layer is a thick muscular layer responsible for propelling contents.
  3. The outer layer is connective tissue, the adventitia.

Seminal Vesicles and the Ejaculatory Duct

The seminal vesicles (vesiculae seminales) are paired accessory glands of the male reproductive system located in the pelvic cavity, posterior to the urinary bladder. Their primary physiological function is the continuous secretion of fluids that contribute to seminal plasma.

Each seminal vesicle has an excretory duct that merges with the vas deferens (ductus deferens). This union forms the single ejaculatory duct (ductus ejaculatorius).

Mnemonic

To remember the parts of the vas deferens: Testicular, Funicular, Inguinal, Pelvic.

Frequently asked questions

What anatomical structure contains the funicular part of the vas deferens?

The funicular part of the vas deferens runs within the spermatic cord (funiculus spermaticus). This structure contains the testicular artery and veins, the artery and vein of the vas deferens, the pampiniform plexus, nerves, lymphatic vessels, the remnant of the processus vaginalis, and loose connective tissue, all enclosed within fascial layers.

What epithelium lines the mucosa of the vas deferens?

The mucosa of the vas deferens is lined by a pseudostratified columnar epithelium, similar to that of the epididymis, featuring tall stereociliated cells and basal cells. The mucosa forms longitudinal folds, and the lamina propria contains a distinct elastic fiber network.

What is the syntopy of the seminal vesicles?

The seminal vesicles lie superior to the prostate gland, between the posterior wall of the urinary bladder and the anterior wall of the rectal ampulla. Their relations include:

  • Rectum (rectum) — separated from the vesicles posteriorly by the rectovesical septum.
  • Vasa deferentia (ducts deferentes) — lie medially along with their ampullae.
  • Ureters (ureteres) — contact the vesicles laterally at their terminal ends.
Where does the ejaculatory duct open?

The ejaculatory duct (ductus ejaculatorius), formed by the union of the vas deferens and seminal vesicle duct, courses obliquely through the base of the prostate gland and opens directly into the prostatic urethra on the seminal colliculus (verumontanum).

Which artery supplies blood to the vas deferens?

Blood supply is provided by the artery of the vas deferens (a. ductus deferentis), typically a branch of the umbilical artery (a. umbilicalis). It runs within the spermatic cord alongside the testicular artery, veins, nerves, and lymphatics.

Where does the vas deferens begin?

The vas deferens originates directly from the tail of the epididymis and extends for up to 50 centimeters.

Where are the seminal vesicles located?

These paired glandular organs are located in the pelvic cavity, directly posterior to the urinary bladder.

How is the ejaculatory duct formed?

The ejaculatory duct (ductus ejaculatorius) is formed by the union of the vas deferens and the excretory duct of the seminal vesicle.

What are the layers of the vas deferens wall?

The wall consists of three layers: an inner mucosa, a thick middle muscular layer, and an outer adventitia.

Go deeper

More topics in Human Anatomy

Middle EarTemporal BoneElbow JointMuscles of the Lateral Abdominal WallParasympathetic Ganglia of the HeadMaxillary NerveOsseous Labyrinth of the Internal EarSubclavian ArteryPleura: Anatomy, Layers, Cavity and BordersMuscles of the Anterior Abdominal WallJoints of the HandMandibular NerveHuman Anatomy →