Each organ of the human body has its own purpose, performing the functions that are necessary to ensure life. The vast majority of organs are complex structures consisting of many interacting components. To understand their functionality, to be able to identify possible pathologies and diseases, you need to know their structure. Knowledge of the anatomy of the portal vein of the liver is one of the points for a correct understanding of the work of an important organ of hematopoiesis and cleansing of the body.
Liver - why and for what?
The liver is one of the most important organs, providing many processes, performing a whole range of functions, without which the body cannot not only function properly, but also live. According to scientific definition, the liver is the largest gland of external secretion, which is found only in humans and vertebrates. One of the main functions of this organ is blood purification, which is also provided by the portal vein system of the liver, which supplies and removes the main physiologicalliquid. This process must take place without a hitch, otherwise the whole body suffers, because the waste blood, in which waste products are removed, is cleared from all unnecessary components - toxins in the body, sent further to the lungs, where it releases carbon dioxide, is saturated with oxygen and is sent back to the circulation. through the body.
Structure of the venous system of the liver
Since the liver is a significant organ of the circulatory system as well, it is permeated with vessels, both large and small, providing supply and outflow of blood. The main structure that carries blood for purification is a vein called the portal vein. It branches into many small vessels that provide blood flow to the special components of the liver - sinusoids, where the detoxification process takes place. The blood then re-enters the bloodstream through the inferior vena cava, traveling further through the body. The variant anatomy of the portal vein, although it implies some difference in its location, in 35% of cases due to congenital features, but in the vast majority they do not affect the quality of its functionality. The scientific name for this bloodstream of the liver would be: portae, which is translated from Latin as "gates" or "doors". The whole system is called "liver vestibule", which characterizes its location and purpose.
Role of the portal vein
The he alth of such an organ as the liver directly affects the general condition of the human body andpossible development of diseases or pathologies. At the same time, the anatomy of the portal vein plays a special role in performing interventional procedures through the skin, in accurate planning of surgical intervention, in particular in liver transplantation.
The role of this main circulatory structure of the liver is enormous, because it collects and delivers blood from the vessels of the subdiaphragmatic part of the digestive tract, up to the location of the lower part of the rectal ampulla, from the pancreas, from the peritoneum, from the spleen and extrahepatic biliary system. The main venous bed of the liver carries the waste blood to the branches of the portal vein. The anatomy of this structure is quite complicated, because the implementation of the processes taking place in the liver is the most important in the blood purification system.
Physiological parameters
Examination of the liver, for example, during ultrasound diagnostics, also involves the study of such a structure as the portal vein system of the liver. It is important not only the location, condition, but also some physiological parameters by which a specialist can judge the he alth or pathologies of an organ. Thus, the diameter of the portal vein of a he althy person is from 11 to 20 mm, with the length of the channel itself from 5 to 8 centimeters. The variability of these architectural indicators should be determined before significant interventions - the outcome of both abdominal and laparoscopic operations on the liver or adjacent organs directly depends on the preliminary diagnosis of the location and featuresthe anatomical structure of an organ such as the portal vein of the liver. The norm will not be in all patients. So, observations and studies have shown that in rare cases there is a complete absence of this section of the circulatory system. Adequate diagnosis of the peculiarities of the location of the vessels of the vestibule of the liver makes it possible to avoid surgical complications, for example, during organ transplantation.
Topography of the main bloodstream of the liver
The supply bloodstream of the liver, which supplies blood for detoxification, is the portal vein. The topographic anatomy of this organ is important for understanding the processes occurring in this most important organ. The large blood vessel that collects and transports blood for detoxification takes its name from its location in the vestibule of the liver, the so-called portal system. The portal vein of the liver, the anatomy of which is taken into account by a specialist during surgical interventions, is located deep in the hepatoduodenal ligament, behind the hepatic artery and common bile duct. There are also nerves, lymph nodes and blood vessels. It is formed from the veins of the following organs located in the abdominal cavity:
- stomach;
- pancreas;
- spleen;
- colon, except for the blood vessels of the anus;
- small intestine.
Having found its true course, the portal vein goes up and to the right, passing behind the upper part of the duodenum and entering the hepatoduodenal ligament, where it passes between its leaves and reaches the gate of the liver.
tributaries of the main vein
Before passing through the portal of the liver, the portal vein is supplemented by the gallbladder vein coming from the gallbladder, the right, left and pyloric veins of the stomach coming out of the stomach. In this case, the left gastric vein in its current is connected to the esophageal veins from the system of the superior vena cava. Further along its course, it anastomoses with the paraumbilical veins, which in the umbilical region connect with the epigastric veins, which are tributaries of the internal thoracic veins and the femoral and external iliac veins. The anatomy of the portal vein and its tributaries make it clear that the blood of the whole body passes through the liver, and the role of this conglomerate of blood vessels in the circulatory system cannot be overestimated.
Division of the portal vein bed
In medicine, it is difficult to draw parallels with other areas of human knowledge and practice. But still, like the bed of any river, the portal vein combines blood vessels, and then, having reached its goal - the vestibule of the liver, it is divided into several blood streams. At first, the division goes into two parts, each of which carries blood to its own lobe of the liver:
- The right branch is called r. dexter. Since the right lobe of the liver itself is somewhat wider than the left, the bloodstream located in it is also larger in size than the relative left. It, in turn, is divided into anterior and posterior branches.
- The left branch of the portal vein is longer than the right one, it is called r. sinister. This blood flow channel branches into a transverse part, from whichvessels depart to the caudate lobe, and the umbilical part, branching into lateral and medial branches, leaving in the parenchyma of the left lobe of the liver.
Both the right and left branches of the portal vein, passing through the body of the liver, branch into many smaller and smaller vessels, through which the process of diffusion detoxification of blood occurs. The blood is then collected by the inferior portal vein. Rather, such a name is not entirely correct. This large vessel that drains blood after cleaning is called the inferior vena cava.
Building features
Science has found that the anatomy of the main vessels of the portal vein system has some variability in each person. This concerns the formation of the portal vein trunk in terms of architectonics and morphometric characteristics and parameters of its roots and tributaries. It is an important part of the study of the portal system, especially for the diagnosis of pathologies, preoperative preparation to reduce complications. Medical scientists have established the fact that the location of the portal vein itself, its tributaries, anastomoses, roots depends on the age of the person and on the existing pathologies of the internal organs. According to some reports, only 30% of people have a portal system architecture that meets generally accepted standards. In other cases, the variant anatomy of the portal vein is diagnosed or detected in the preoperative or surgical periods. Such deviations in most cases are not pathological in nature and do not affect the functionality of the liver and other organs. Alsoa feature of the portal hepatic structure of the circulatory system of the body is the abundance of anastomoses - connections of the vena cava.
Deviations from the norm and pathology
When conducting research or operations and collecting the information received into a single whole, scientists found that in extremely rare cases, and there are only about 30 of them around the world, a person has no portal vein at all. In most cases (about 70%), the variability of this bloodstream is manifested in various combinations of anastomoses and in the size of the vein itself. But in addition to the genetically determined features of the portal system, pathological changes can develop in it that affect the state of the whole organism.
Thrombosis of the portal system affects many people, because blood clots and cholesterol are formed as a result of many reasons, such as malnutrition, disorders in the gastrointestinal tract, excretory system. Pilethrombosis can occur in two forms:
- chronic progressive - the blood flow is partially blocked, the movement of blood is difficult, which affects the state of the whole organism;
- complete thrombosis - the lumen of the portal vein is completely blocked, which causes a sharp deterioration in he alth, up to death.
Signs of portal vein thrombosis are pain in the right hypochondrium, nausea, vomiting, fever, enlargement of the spleen (splenomegaly) due to increased blood flow in this organ. These symptoms appear simultaneously, worsening the gener althe patient's he alth condition. Complete thrombosis causes intestinal infarction.
Chronic course of pyletrombosis often does not have acute symptoms. This occurs due to the activation of compensatory mechanisms, when other vessels take over the work of the portal vein. When the possibilities of compensators are exhausted, ascites, dilatation of the saphenous veins of the esophagus and the anterior abdominal wall, implicit abdominal pain and subfebrile temperature appear.
The consequences of chronic pylethrombosis are progressive chronic ischemia and cirrhosis of the liver (in cases where this disease was not the source of pylethrombosis).
The liver itself does not have nerve endings capable of signaling problems with pain. Therefore, preventive examinations should be a source of early detection of potential problems.
How is the diagnosis made?
The structure of the human body, including the anatomy of the portal vein, has long been studied through postvital studies. Modern technologies make it possible to examine this structure of the body in a non-invasive way for diagnostic purposes, as well as for preoperative preparation in order to reduce the negative complications of surgical intervention. Examination of the liver and portal vein is performed using the following techniques:
- general blood test;
- blood test biochemical;
- angiography;
- doppler;
- magnetic resonance computed tomography;
- ultrasonicdiagnostics.
One of the most common research methods is ultrasound. With its help, most pathologies are established, as well as the need for more informative examination methods. It is quite cheap and informative, does not require a complex preparatory period and is absolutely painless.
Angiographic methods are methods for studying the state of blood vessels using research equipment, an X-ray machine, a CT scanner and a contrast agent.
Doppler is an additional ultrasound technique aimed at assessing the intensity of blood flow in the circulatory system of the vessels.
Magnetic resonance computed tomography is the most accurate way to obtain an image from sections of an organ or structure under study. Allows you to identify the state of tissues, the presence of neoplasms or pathologies of the architecture of the organ.
Methods for examining the portal vein are selected taking into account the patient's complaints, the results of previous studies.
Possible therapy for channel disturbances
Treatment of the portal vein is a whole range of medical measures, depending on the stage of the disease, identified comorbidities, the general he alth of the patient, and anamnesis collected by a specialist. In total, it consists of components such as:
- Taking anticoagulants - drugs that promote vessel recanalization and inhibit the adhesion of platelets and cholesterol into plaques. These are drugs such as heparin,pelentan.
- Thrombolytics - medicinal substances that dissolve existing blood clots and serve as a prevention of their re-formation, for example, streptokinase, urokinase.
- Surgical intervention by performing transhepatic angioplasty, thrombolysis with intrahepatic portosystemic shunting. It is prescribed in case of ineffectiveness of medical treatment or acute form of pylethrombosis.
Many patients suffering from impaired hepatic portal vein blood flow require treatment for complications, and these may be bleeding from the tributary veins or intestinal ischemia. These pathologies are treated surgically followed by a recovery period and lifelong relapse prevention.
The anatomy of the portal vein includes a complex set of blood vessels that deliver blood to the liver for detoxification. Modern non-invasive methods of diagnosing this complex make it possible to exclude as completely as possible possible complications during surgical interventions, as well as to identify existing deviations, neoplasms, and violations of the blood flow lumen in time to prevent the development of pathologies and diseases that at some point may become irreversible.
It is impossible to overestimate the role of the portal vein in the circulatory system - it is responsible for collecting and supplying blood for detoxification in the liver cells. Without its normal functioning, it is impossible to achieve the general well-being of a person.
