Vas Deferens – Tutorial
Please read Unit 12 – Introduction to Male Reproductive System Tissues prior to completing the activities in this chapter.
Introduction to the Vas Deferens
The vas deferens (ductus deferens) is a tube that temporarily stores and protects sperm as they continue to mature and gradually transports them from the epididymis to the lumen of the proximal urethra. The vas deferens measures only 2-3 mm in diameter but is relatively long (approximately 15-18 inches or 35-45 cm in length) as it takes a circuitous route from the epididymis to the urethra. Each vas deferens starts inferior to the testis as a continuous connection to the epididymis. The vas deferens then ascends through the inguinal canal and enters the lower abdominopelvic cavity where it loops over (superior to) the ureter and then descends medially along the posterior wall of the urinary bladder. The vas deferens ends at the point where it merges with an excretory duct from the seminal gland to form the ejaculatory duct which discharges sperm into the proximal urethra during ejaculation. The final segment of the vas deferens just before the ejaculatory duct has an enlarged lumen and is known as the ampulla of the vas deferens. The ampulla of the vas deferens can store sperm for several months if necessary.
The wall of the vas deferens has a thick layer of smooth muscle relative to its total diameter which produces peristaltic contractions that move sperm and fluid along the lumen of the vas deferens toward the urethra. The lumen of the vas deferens is lined with pseudostratified ciliated columnar epithelium which appears very similar to the endothelium of the epididymis.
Tutorial: Use the image slider below to learn more about the structure and characteristics of the vas deferens.
Microscopy: Use the image slider below to learn how to use a microscope to study the vas deferens on a microscope slide.
