What is the Difference Between Epididymis and Vas Deferens

The main difference between epididymis and vas deferens is that epididymis stores and moves sperms from the testes, whereas vas deferens moves sperms out of the scrotal sac. 

Epididymis and vas deferens are two tubes that carry sperm out of the testicles. They are important parts of the male reproductive system. 

Key Areas Covered

1. What is Epididymis
     – Definition, Structure, Function
2. What is Vas Deferens
     – Definition, Structure, Function
3. Similarities Between Epididymis and Vas Deferens
     – Outline of Common Features
4. Difference Between Epididymis and Vas Deferens
      – Comparison of Key Differences

Key Terms 

Epididymis, Ductus Deferens, Vas Deferens

What is Epididymis

The epididymis is a coiled, long tube that stores and moves sperm from the testes. It occurs as a curved structure on the back margin of the testes. The epididymis is smaller, containing larger and less densely packed tubes than the testes. There are three sections of the epididymis. They are the head, body, and tail. The head part occurs near the top of the testes. It stores sperm for maturation. However, the body of the epididymis is a long, twisted part that undergoes sperm maturation. Sperm maturation takes around one week. The tail of the epididymis connects to the vas deferens, another tube that moves sperms out of the testicles.

Figure 1: Parts of the Epididymis

Furthermore, the length of the epididymis is 6-7 m. Tunica vaginalis is the thin tissue that separates the epididymis from the testes. Pseudostratified columnar epithelium lines the walls of the epididymis. 

What is Vas Deferens

The vas deferens (or ductus deferens) is a major component of the male reproductive system. It occurs within the spermatic cord. It is also connected to the epididymis and helps to move sperms to the urethra. A branch of the superior vesical artery supplies blood to the vas deferens. Moreover, the testicular vein collects the deoxygenated blood from the vas deferens. The lumbar and external iliac lymph nodes collect lymphatic drainage from the vas deferens. In addition, pseudostratified columnar epithelium lines the walls of the vas deferens. Most importantly, the function of the vas deferens is to move sperms.

Figure 2: Vas Deferens

During ejaculation, the smooth muscles in the vas deferens wall contract reflectively, propelling sperms forward. It is known as peristalsis. When passing to the urethra, sperms mix with other secretions of the male reproductive system. These secretions include the seminal vesicles, prostate gland, and bulbourethral glands, which form the bulk of semen.

Similarities Between Epididymis and Vas Deferens

• Epididymis and vas deferens are two tubes of the male reproductive system.
• They are important to move sperms out of the reproductive system.
• They are lined by pseudostratified columnar epithelium.

Difference Between Epididymis and Vas Deferens

Definition

Epididymis refers to a highly convoluted duct behind the testis along which the sperm passes to the vas deferens. In contrast, vas deferens refers to the duct which conveys sperm from the testicle to the urethra.

Occurrence

Epididymis occurs between the testicles and vas deferens, while vas deferens occurs between the epididymis and urethra. 

Structure

The three parts of the epididymis are the head, body, and tail, while the vas deferens is a muscular tube within the spermatic cord. 

Function

Epididymis stores sperm for maturation and moves to the vas deferens, while the vas deferens transfers sperm to the urethra in preparation for ejaculation. 

Conclusion

In brief, epididymis and vas deferens are two tubes that move sperms out of the testicles through the male reproductive system. Epididymis occurs between the testicles and vas deferens. It contains three parts: head, body, and tail. It helps sperm maturation by storing sperm and moving sperm to the vas deferens. In comparison, the vas deferens is a muscular tube between the epididymis and urethra. It occurs within the spermatic cord. The primary function of the vas deferens is to move sperms to the urethra to prepare ejaculation. Therefore, the main difference between epididymis and vas deferens is their occurrence. 

References:

1. Team, T. H. E.. Epididymis function, Definition & anatomy | Body Maps. Healthline. 
2. Charlotte O’Leary BSc, Mbc.  Vas deferens (ductus deferens). Kenhub. 

Image Courtesy:

1. “Epididymis-KDS” By KDS444 – Own work (CC-BY SA 3.0) via Commons Wikimedia
2. “Male genital system – Front view” By R. Dewaele (Bioscope, Unige), J. Abdulcadir (HUG), C. Brockmann (Bioscope, Unige), O. Fillod, S. Valera-Kummer (DIP), www.unige.ch/ssi – Own Work (CC-BY SA 4.0) via Commons Wikimedia