Duct system of Male Reproductive Tract

The male reproductive system consists of a pair of testes (primary sex organs) and a series of accessory ducts that transport spermatozoa from the seminiferous tubules to the exterior of the body.

The accessory ducts associated with the male reproductive system include:

Rete Testis → Vasa Efferentia → Epididymis → Vas Deferens → Ejaculatory Duct → Urethra → Urethral Meatus

Sperm are produced in the seminiferous tubules of the testes. These tubules unite to form straight tubules (tubuli recti), which open into the rete testis. From here, sperm travel through the entire duct system until they are expelled through the urethral meatus (external opening).

• The seminiferous tubules of each lobule converge to form a tubulus rectus (straight tubule), which conveys sperm into the rete testis.
• The rete testis is a tubular network located on the posterior side of the testis.
• The vasa efferentia arise from the rete testis.

• The rete testis fuses to form 10–20 efferent ductules called vasa efferentia (also called ductuli efferentes).
• These ductules emerge from the upper dorsal (posterior) surface of the testis.
• They open into common tubules that are highly coiled to form the epididymis.

The epididymis is a single, highly coiled tube (~20 feet / ~6 metres) attached to the posterolateral side of the testis.

It temporarily stores spermatozoa and is the site where sperm undergo physiological maturation, acquiring increased motility and fertilising capacity.

Three Parts of Epididymis:

Functions of Epididymis

1. Serves as a duct for passage of sperm from testis to vas deferens.
2. Stores sperm prior to ejaculation; storage makes sperm motile and mature.
3. Epididymis pushes sperm into vas deferens by peristaltic and segmenting contractions.
4. Spermatozoa are produced continuously; if not ejaculated, they are reabsorbed.

• Arises from the tail (cauda) of the epididymis.
• A partially coiled, long tube (~40 cm) – coiled at the start, becomes straight as it enters the abdominal cavity through the inguinal canal.
• Runs upward into the abdominal cavity, then passes over the urinary bladder.
• Near its end, the vas deferens dilates to form an ampulla – for temporary storage of sperm.
• Joins the duct of the seminal vesicle to form the ejaculatory duct.

• A thin-walled tube, ~2 cm long.
• Formed by the union of the seminal vesicle duct and the vas deferens.
• Both ejaculatory ducts pass through the prostate gland and open into the urethra.
• Carries sperm mixed with seminal vesicle secretions.

• Arises from the urinary bladder and joins the ejaculatory duct to form the urinogenital canal.
• Carries both urine and sperms + secretions of seminal vesicles, prostate gland, and Cowper's gland.
• Extends through the penis and opens at the urethral meatus (external opening).
• Length: ~20 cm.

Three Regions of Urethra:

Has two sphincters:

• Internal sphincter - smooth muscle fibres, at the beginning of urethra
• External sphincter - striated muscle fibres, around the membranous part