Each organ of the human body has its purpose, performing those functions that are necessary to ensure vital functions. The vast majority of organs are complex structures consisting of many interacting components. To understand their functionality, to be able to determine possible pathologies and diseases, you need to know their structure. Knowledge of the anatomy of the portal portal vein of the liver is one of the points of a correct understanding of the work of an important organ of blood formation and body cleansing.
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 can not only function correctly, 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 portal vein system of the liver, which supplies and removes the main physiological fluid. This process should take place without hitch, otherwise the whole body suffers, because the spent blood, in which waste products are removed, is cleaned of all unnecessary components - toxins in the body, sent to the lungs, where it gives off carbon dioxide, is saturated with oxygen and is sent back to the circuit in the body.
The structure of the venous system of the liver
Since the liver is an important organ of the circulatory system as well, it is penetrated by vessels, both large and small, providing blood supply and outflow. The main structure that carries blood for purification is a vein called the portal vein. It branches into many small vessels that provide blood to the special components of the liver - the sinusoids, where the detoxification process takes place. Then the blood again enters the bloodstream through the inferior vena cava, traveling further through the body. Variant anatomy of the portal vein, although it suggests a slight 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 functional. The scientific name of this bloodstream of the liver will be: portae, which from Latin translates as “gate” or “door”. The whole system is called the "vestibule of the liver", which characterizes its location and purpose.
Portal vein role
The health of an organ such as the liver directly affects the general condition of the human body and the possible development of diseases or pathologies. At the same time, the anatomy of the portal vein plays a special role in the implementation of interventional procedures through the skin, in the exact planning of surgical intervention, in particular, in liver transplantation.
The role of this main circulatory structure of the liver is huge, because it is it that collects and delivers blood from the vessels of the subphrenic part of the digestive tract, up to the location of the lower part of the rectal ampoule, from the pancreas, from the peritoneum, from the spleen and extrahepatic biliary system. The main venous channel of the liver carries spent blood in the branch of the portal vein. The anatomy of this structure is quite complicated, because the implementation of the processes taking place in the liver is most important in the blood purification system.
Physiological parameters
Examination of the liver, for example, during ultrasound diagnostics, involves the study of such a structure as the portal 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 health or pathologies of the organ. So, the diameter of the portal vein of a healthy person is from 11 to 20 mm with a 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 operations of both abdominal and laparoscopic operations on the liver or adjacent organs directly depends on preliminary diagnostics of the location and features of the anatomical structure of such an organ as the portal vein of the liver. The norm will not be in all patients. Thus, observations and studies have shown that in rare cases there is a complete absence of this department of the circulatory system. Adequate diagnosis of the features of the location of the vessels of the vestibule of the liver avoids surgical complications, for example, during organ transplantation.
Topography of the main bloodstream of the liver
The supplying bloodstream of the liver, supplying blood to cleanse toxins, is the portal vein. The topographic anatomy of this organ is important for understanding the processes taking place in this most important organ. A large blood vessel that collects and transports blood for detoxification has its name due to the location of the so-called portal system on the threshold of the liver. 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 hepatic-duodenal ligament, located behind the hepatic artery and common bile duct. There are 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 blood vessels of the anal canal;
- 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 hepatic-duodenal ligament, where it passes between its leaves and reaches the portal of the liver.
Tributaries of the main vein
Before the gate of the liver passes, the portal vein is supplemented by the gallbladder vein coming from the gallbladder, the right, left, and pyloric veins of the stomach leaving the stomach. In this case, the left gastric vein in its current connects to the esophagus veins from the superior vena cava system. Further along its channel, it anastomoses with umbilical veins, which in the umbilical region are connected to the epigastric veins, which are inflows of the internal chest veins and the femoral and external iliac veins. The anatomy of the portal vein and its tributaries makes 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
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 connects the blood vessels in itself, and then, having reached its goal - the threshold of the liver, it is divided into several blood flows. At first, the separation goes into two parts, each of which carries blood to its share 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 larger in size relative to the left. It, in turn, is divided into anterior and posterior branches.
- The left branch of the portal vein is longer than the right, it is called r. sinister. This channel of blood flow branches into the transverse part, from which the vessels depart to the caudate lobe, and the umbilical part, branching into the lateral and medial branches, leaving into the parenchyma of the left liver lobe.
Both the right and left branches of the portal vein, passing through the body of the liver, branch into many smaller vessels, through which the process of diffusion detoxification of blood occurs. Then the lower portal vein collects blood. Rather, such a name is not entirely correct. This large blood-draining vessel is called the inferior vena cava.
Structural features
Science has found that for every person the anatomy of the great vessels of the portal vein system has some variability. This concerns the formation of the portal vein trunk in terms of architectonics and morphometric characteristics and parameters of its roots and tributaries. This is an important part of the study of the portal system, especially for the diagnosis of pathologies, preoperative preparation to reduce complications. A medical scientist has established the fact that the location of the portal vein itself, its tributaries, anastomoses, and 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, variant anatomy of the portal vein is diagnosed or detected in the preoperative or surgical periods. Such deviations in most cases are not pathological and do not affect the functionality of the liver and other organs. Also a feature of the portal liver structure of the circulatory system of the body is the abundance of anastomoses - vena cava connections.
Deviations from the norm and pathology
When conducting research or operations and collecting the information received as a whole, scientists found that in extremely rare cases, and there are only about 30 of them registered around the world, a person has completely no portal vein. In most cases (about 70%), the variability of this bloodstream manifests itself in various combinations of anastomoses and in the size of the vein itself. But in addition to genetically determined features of the portal system, pathological changes can develop in it that affect the state of the whole organism.
Many people suffer from thrombosis of the portal system, because blood clots and cholesterol are formed as a result of many reasons, such as malnutrition, disorders of the gastrointestinal tract, and excretory system. Pilot thrombosis can occur in two forms:
- chronic progressive - blood flow is partially blocked, blood flow is difficult, which affects the state of the whole organism;
- complete thrombosis - the portal vein lumen is completely blocked, which causes a sharp deterioration in the state of health until death.
Signs of portal vein thrombosis are pain in the right hypochondrium, nausea, vomiting, fever, enlarged spleen (splenomegaly) due to increased blood flow in this organ. These symptoms appear simultaneously, worsening the general health of the patient. Complete thrombosis causes intestinal infarction.
The chronic course of pilothrombosis often does not have acute symptoms. This occurs due to the activation of compensatory mechanisms, when other vessels take on the work of the portal vein. When the possibilities of compensators are depleted, ascites appears, expansion of the saphenous veins of the esophagus and anterior abdominal wall, implicit abdominal pain and low-grade fever.
The consequences of chronic form pilothrombosis are progressive chronic ischemia and cirrhosis of the liver (in cases where this disease has not become a source of pilothrombosis).
The liver itself does not have nerve endings that can painfully signal problems. Therefore, preventive examinations should be a source of timely identification of potential problems.
How is the diagnosis carried out?
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 body structure non-invasively 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 carried out using the following methods:
- general blood test;
- biochemical blood test;
- angiography;
- dopplerometry;
- magnetic resonance computed tomography;
- ultrasound diagnostics.
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 difficult preparatory period and is absolutely painless.
Angiographic methods are methods for examining the state of blood vessels using research equipment, an X-ray machine, a computer tomograph, and a contrast agent.
Dopplerometry is an additional ultrasound technique aimed at assessing the intensity of blood flow in the circulatory system of blood vessels.
Magnetic resonance computed tomography is the most accurate way to obtain images from sections of the organ or structure under study. It allows to identify the state of tissues, the presence of neoplasms or pathologies of the organ architecture.
Methods for examining the portal vein are selected taking into account the patient's complaints, the results of previous studies.
Possible treatment of channel disorders
The portal vein treatment is a whole complex of medical measures, depending on the stage of the disease, identified concomitant pathologies, the general state of the patient’s health, and an anamnesis collected by a specialist. In total, it consists of such components as:
- Reception of anticoagulants - drugs that promote vascular recanalization and inhibit platelet and cholesterol adhesion into plaques. These are drugs such as heparin, pelentan.
- Thrombolytics are drugs that dissolve existing blood clots and serve as a prophylaxis for their re-formation, for example, streptokinase, urokinase.
- Surgical intervention by means of transhepatic angioplasty, thrombolysis with intrahepatic portosystemic shunting. It is prescribed in case of ineffective drug treatment or acute form of pilothrombosis.
Many patients suffering from impaired blood flow to the portal portal vein of the liver require treatment of complications, and this may be bleeding from veins, tributaries or ischemia of the intestine. These pathologies are treated surgically with a subsequent recovery period and lifelong prevention of relapse.
The anatomy of the portal vein includes a complex complex of blood vessels that delivers blood to the liver for detoxification. Modern non-invasive diagnostic methods for this complex make it possible to completely exclude possible complications during surgical interventions, as well as timely identify deviations, neoplasms, and violations of the blood flow to prevent the development of pathologies and diseases, which 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 a general well-being of a person.