The intramural part of the ureter is the most distal part of the organ, located in the thickness of the surface of the bladder and opening into its cavity with the help of the mouth. The length of this section is about 1.5-2 cm. The intramural section is one of four zones of physiological constrictions in the organ (except for the intramural part, similar constrictions are observed in the juxtavesical section, in the areas of the transition of the pelvis to the ureter and the interlacing with the iliac vessels).
The importance of the department
In clinical medicine, the importance of the intramural ureter is due, firstly, to the fact that it is a natural antireflux mechanism that does not allow urine to flow back during urination in healthy people with an increase in intravesical pressure. Secondly, in this section, the presence of small calculi is most often observed, which, due to general innervation with the bladder, can clinically manifest itself not only in the form of renal colic, but also in the form of dysuria. The intramural ureter - where is it? And what is this? Consider all these issues in more detail, tell about the features of the treatment of urolithiasis.
What it is?
Here is a brief description. The ureter is a urinary paired organ that serves to remove urine from the kidneys into the cavity of the bladder. First, the upper sections are filled with urine, and due to contractions of the muscle structures in its wall, urine moves further into the cavity of the bladder, even if the person is in this horizontal position.
The ureter is divided into three departments: distal, abdominal and pelvic. The abdominal is localized in the retroperitoneal wall behind the abdomen and is adjacent to the lumbar muscles. It begins behind the duodenum, and closer to the pelvic zone passes behind the mesentery of the sigmoid colon. The pelvic section in women is located behind the ovaries, it surrounds the uterus on the sides, runs along its wide ligament, in the lumen between the bladder and the vaginal wall. The difference between the abdominal ureter in men is that the tubes of this organ are located outside the seminal ducts, and enter the bladder above the upper side of the seminal bladder.
The distal area of the organ is the most distant from the kidneys, and the second name of this site is the “intramural section”. It is localized directly in the thickness of the bladder wall and its length is only 1.5–2 cm.
Structure
The ureter in the anatomy of the human body is a very important structure connecting the kidneys to the bladder. This is a paired tubular hollow organ, which is a muscle connective tissue. Its length is approximately 25 to 35 cm. The diameter, which has no anatomical pathologies, varies on average from 2 to 8 mm.
The features of the organization of the muscular structures of the ureter are such that it consists of:
- external muscle tissue;
- internal muscle tissue;
- vessels that supply the body;
- mucosal epithelial layer.
Outer layer
The outer layer is covered with adventitia and fascia, and in the intraparietal areas the mucous membrane is anatomically divided into:
- transitional epithelial layer, which is located in the body in several rows;
- epithelial plates containing elastic collagen fibers of muscle tissue.
Thus, the entire inner part of this hollow organ is composed of many longitudinal folds that provide an inextricable stretching of the parts of the ureter, so that the outflow of urine into the kidney is not allowed. What are the features of the organization of the muscular structures of the ureter?
The structure of the muscle layers
Directly muscle tissue, which is the basis for the structure and normal functioning of the ureters. These are peculiar bundles of muscle cells of different thicknesses, which can be located as follows:
- askew;
- longitudinally;
- transversely.
The upper layers of muscle tissue consists of two interpenetrating sublayers: circular and longitudinal. The lower, inner part of the muscle layer contains three sublayers - two longitudinally located and one circular layer of cells between them. Between the bundles of myocyte cells in the muscles there are nexus cells that have a connecting function, they also pass through the epithelial plates and through adventitia.
The ureter in men is 2-3 cm longer than in women, and the right ureter in all people is 1-1.5 cm shorter than the left, because the activity and development of the left kidney is always higher.
The lumen of the organ cavity also varies, in the context it resembles an accordion. The most significant narrowing of the internal gaps are located:
- behind the pelvis;
- in the place of the beginning of the pelvic and the end of the abdominal part;
- at the entrance to the bladder.
It is these narrowed sections of the ureter, including the intramural section, that are most often exposed to various pathologies, infections and congestion. The diameter of the bottlenecks varies from 2 to 4 mm, but they have the ability to expand to 8 mm.
The abdominal and pelvic areas are different in diameter of the internal cavity:
- behind the abdominal wall - from 6 to 8 mm, and the expansion of this part can reach up to 14.5 mm;
- organs passing in the pelvic area have an internal clearance of approximately 4 mm, with an extension of up to 8 mm.
Blood supply to the area
Arterial blood fills and nourishes all departments of the ureters. The vessels are located in the adventitious part of the membrane, and from them pass into the capillary organ.
In the upper part, arterial branches emanate from the renal artery. The middle section is connected by a common internal iliac artery and the abdominal aorta. The lower portion is fed by branches of the iliac arteries, such as the cystic, uterine, and rectal. In the abdominal region, the plexus of vessels is located in front of the ureter, and in the pelvic region behind it.
As for the venous blood flow, it is provided by the veins of the same name located near the arteries. Blood from the lower part of the organ goes into the iliac internal veins, and from the upper into the testicular. The flow of lymph is provided by the lumbar and internal iliac lymph nodes.
Features of the functioning of the body
The functions of the ureter are controlled by the autonomic nervous system. The branches of the vagus nerve are suitable for the upper part of this organ, and the lower part is innervated by the pelvic nerve plexuses. The main function of the ureters is to push fluid from the renal pelvis to the bladder, which is provided by contractions of muscle tissue cells. The rhythm of such contractions is determined by the cells of the pelvis-ureteric segment, but it can vary depending on:
- the work of the kidneys, that is, the speed at which urine is filtered;
- the location of the body, that is, the person is standing, sitting or lying;
- conditions of the urethra and bladder;
- the work of the autonomic nervous system.
A direct effect on the functionality of an organ is exerted by the level of calcium in the body. The strength with which the ureter is reduced depends on the concentration of calcium in muscle tissue, and the calcium content in the cells provides equal pressure in the kidneys, where the ureter begins, and throughout its length, and in the bladder.
The norm is pumping urine in a volume of 10-14 ml per minute. As for internal pressure, it can "adapt" to the kidneys, and in the bladder cavity to the ureters. The process is called vesicoureteral reflux, and its appearance causes painful sensations and physiologically unpleasant moments.
Stone in the intramural ureter
Ureterolithiasis (stones in this organ) is dangerous with serious and serious complications. The stones that violate the passage of urine cause loosening of the mucous membrane of the organ, hypertrophy of the muscle walls, hemorrhages in the submucous layer. Over time, such changes lead to atrophy of the nerve and muscle fibers of the ureter, a decrease in its tone, hydroureteronephrosis, and ureterotectasia.
The most common localization of stones that formed in the kidneys and displaced this organ are narrowing sites. Mostly it is its mouth - the intramural ureter. Here calculi often stop, and the patient needs medical attention to remove them.
Treatment of this pathology
Dissolution of calculi of the intramural section of the right ureter or left ureter can be carried out with drugs, but this condition is usually very painful. In this case, surgical assistance is often required (if the stone is large), or an increase in the patient's motor activity, so that the calculus quickly passes through the mouth into the bladder.
With planned treatment, stones in the intramural ureter can be expelled with medication. This method is used for grinding formations. Small grains of sand come out themselves completely painlessly. Those that are larger, under the influence of drugs break up into fragments.
A method for the treatment of urolithiasis
Urate stones in the development of urolithiasis in most cases are eliminated with allopurinols (Zilorik, Sanfipurol). Such medicines as Blemaren, Kanefron N and Urolesan quickly act. Phosphate calculi breaks down the medicine "Marelin", which is made on the basis of plant materials. Oxalate stones are removed with the help of the "Spill" medication and means for alkalizing urine. In the treatment of cystine formations, "Tiopronin" and "Penicillamine" are prescribed.
To accelerate the exit of stone from the lumen of the ureter, it is recommended to take antispasmodics - “Papaverine”, “No-shpa”. At the same time, the muscles of these hollow structures relax, and their lumen expands, which contributes to the advancement of stones. In complex cases, surgical intervention or crushing of kidney stones in the intramural ureter is prescribed.