Vas deferens
| Vas deferens | |
|---|---|
Human male reproductive system | |
Vertical section of the testis, to show the arrangement of the ducts. | |
| Details | |
| Precursor | Wolffian duct |
| Identifiers | |
| MeSH | D014649 |
| TA | A09.3.05.001 |
| FMA | 19234 |
| Anatomical terminology | |
The vas deferens (or ductus deferens) [1] is a duct in the body of man. It is also in other male vertebrates. Its function is to carry sperm away from the testes, towards the penis. Sperm that are removed from the vas deferens might swim in circles.[2]
Mature sperm is stored in the vas deferens. If sperm are removed from the start of the vas deferens (the cauda epididymis) they might also display movement which seems directive, like they are swimming in a direction on purpose.[2] Maturation is a complex process and has been getting much attention since at least before 1965.[2]
Function during ejaculation
During ejaculation, the smooth muscle in the wall of the vas deferens contracts. That pushes the sperm toward the penis. This is a ciliary action, where the cilia push the cell along the surface.[2] This is also known as peristalsis.[3] The sperm go from the vas deferens into the urethra when the penis is ejaculating.[4]
Other male sex glands activate (which might be to change shape, secrete, etc., or both) at the same time as the vas deferens. For example the bulbous gland secrete prejaculate during sexual intercourse for lubrication. This secretion also helps the mature sperm (which prefer an alkaline environment) survive in the slightly acid environment of the vagina. The prostate, and female sexual organs, help with lubrication too.
The vas deferens is part of the spermatic cord. To reach the urethra, sperm must travel through the ejaculatory ducts.[4]
Anatomy
There are two of the ducts, which are tubes surrounded by smooth muscle. The smooth muscle protects the vas deferens. They connect the left and right epididymis to the ejaculatory ducts in order to move sperm.
- [4][5]
- the vas deferens and ejaculatory duct are part of the spermatic cord. It transports mature sperm to the urethra during ejaculation
- It runs from the epididymis into the pelvic cavity, to the urethra when the penis is ejaculting. This is posterior to the bladder
- The spermatic cord transports mature sperm to the urethra during ejaculation.
Sperm goes to the vas deferens from the testes to be stored as mature sperm until it is time to ejaculate. The sperm goes to the vas deferens upwards, along the posterior (front) of the testicles.[5]
Vasectomy
There is a surgery called vasectomy that is a method of contraception. The two vasa deferentia (Latin plural) are cut and sealed, so the sperm cannot get out of the body. This is usually permanent, but in some cases, it can be reversed. Sometimes instead of cutting the vasa deferentia, the surgeon puts something to block the sperm instead of cutting them.
Notes
- ↑ Latin: "carrying-away vessel"
- ↑ 2.0 2.1 2.2 2.3 Gray, Henry; Williams, Peter L.; Bannister, Lawrence H., eds. (1995). Gray's anatomy: the anatomical basis of medicine and surgery (38th ed ed.). New York: Churchill Livingstone. ISBN 978-0-443-04560-8.
{{cite book}}:|edition=has extra text (help) - ↑ Berridge, Michael J. (2008). "Smooth muscle cell calcium activation mechanisms". The Journal of Physiology. 586 (21): 5047–5061. doi:10.1113/jphysiol.2008.160440. ISSN 1469-7793. PMC 2652144. PMID 18787034.
- ↑ 4.0 4.1 4.2 "Vas Deferens: Function, Anatomy & Conditions". Cleveland Clinic. Retrieved 2025-05-01.
- ↑ 5.0 5.1 "Vas Deferens - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 2025-05-01.