The vas deferens is a paired organ that is part of the system of the vas deferens of the epididymis and testicles, as well as an integral part of the epididymis. This duct ends at the junction with the seminal vesicle canal.
The vas deferens is one of the main tools for controlling the male reproductive system. The final part of it forms an ampulla in the form of a spindle, which is part of the prostate gland and converges with the excretory canal of the seminal vesicle. The unifying duct is called the ejaculatory duct.
Length
The length of the vas deferens is 45 - 50 centimeters. In the transverse section, it does not exceed three millimeters, and the diameter of the lumen is no more than half a millimeter. The walls of the named duct are significantly thickened, and in this regard, it is easily palpable on the surface of the spermatic cord from the scrotum to the ring of the inguinal canal.
The anatomy of the vas deferens is of interest to many, so let's take a closer look at its structure.
Four sections of the duct
Based ontopographic data of the vas deferens, four of its departments are distinguished:
- The first section is called the initial (shortened testicular part). It is located behind the testicle, closer to its appendages. This is the smallest section, located at the back of the testicle.
- Further, if ascending cranially (vertically), it is followed by the cord section. It is located within the spermatic cord, closer to the middle part of its vessels, and stretches to the inguinal ring located on the surface. It should be noted that the structure of the vas deferens is unique.
- After that, the duct enters the inguinal canal (inguinal part). Coming out of which, it stretches through the inguinal ring, goes through the small pelvis, and more specifically, through its side wall to the lower part until it joins the excretory canal of the seminal vesicle. This section of the duct is called the pelvic duct. The pelvic region (pars pelvina) starts from the inside of the opening of the inguinal canal and ends with the prostate gland. It is devoid of the choroid plexus and extends through the parietal sheet of the peritoneal part of the small pelvis. The final part of the duct that carries the seed is located near the bottom of the bladder and becomes wider, resembling an ampulla.
- The vas deferens in the pelvic area is located in the retroperitoneal space extraperitoneally (that is, only in one part). Towards the prostate from the lateral side (side) it bypasses the shaft of the inferior epigastric artery, connects with the iliac artery and vein,passes between the rectum and the bladder, crosses with the ureter, gets to the bladder and reaches the base of the prostate gland, being near the same duct on the other side. This terminal part of the vas deferens is dilated, spindle-shaped, and forms the ampulla of the vas deferens.
The length of the ampoule is 30-40 millimeters, and its largest transverse dimension reaches ten millimeters. In the lower distal (most distant) part of the vessel, it gradually becomes narrow, penetrating into the thick layer of the prostate gland and connecting with the excretory duct of the seminal vesicle.
The single duct is called the ejaculatory duct. Two of them enter the prostatic urethra near the seminal tubercle and extend into the lower part through the posterior region of the prostate. The length of each of the ejaculatory ducts is 2 cm. The inner diameter is 1 mm in its original part and 0.3 mm at the point of its entry into the urethra.
Wall structure
The wall of the duct that carries the seed is formed by mucous, muscular and adventitious membranes. The first of them is three to five longitudinal folds. In the place of the vessel of the described duct, the mucous membrane forms bay-shaped tubercles, which are called ampulla diverticula.
The muscular layer is located in the outer part of the mucosa, it is formed by means of the inner, middle circular and outer longitudinal layerssmooth muscle cells. The muscular sheath supplies the wall of the vas deferens with almost cartilaginous density. The muscular membranes of the vessel of this duct are not so clearly represented. From the outside, its wall is formed by an adventitious membrane, which smoothly passes into the connecting layer of the surrounding duct.
Destination of the duct
Through the vas deferens, mature, immobile spermatozoa with an acidic fluid, as a result of contraction of the duct wall, exit the epididymis and are stored in the duct vessel. It should be noted that the liquid present there is partially absorbed.
Provision of the duct and seminal vesicle with nerve cells is sympathetic (this system is formed from the upper and lower hypogastric plexuses), as well as parasympathetic (through the pelvic splanchnic nerves).
Blood supply duct
The blood supply of the vas deferens (the photo is presented in the article) occurs due to the ascending branch of the artery, the middle rectal artery and the inferior vesical.
The seminal vesicle is also supplied by branches of the superior and middle rectal arteries and the inferior vesical artery.
The veins of the seminal vesicles of the male reproductive system enter the plexus of the veins of the bladder, and the veins of the vas deferens flow into the tributaries of the internal iliac vein.
Physiology of seminal vesicles
Seminal vesicles are glandularandrogen-dependent organs, the secretion of which consists of a viscous, white-gray jelly-like substance, which, after ejaculation, becomes liquid in a few minutes and forms 50-60 percent of sperm. The main function of the seminal vesicles is the secretion of fructose, the level of which reflects the androgenic saturation of the body.
Seminal vesicles also secrete other components of sperm, namely:
- nitrous substances;
- inositol;
- proteins;
- ascorbic acid;
- prostaglandins.
Seminal vesicle secretion along with testicular secretion is a protective colloid, creating greater resistance for spermatozoa.
