Medical Health Information

In the fetus, the liver develops from the hepatic diverticulum, and draws blood from the arteries that carry blood from the vitelline yolk sac. Top diverticulum causes hepatocytes and bile ducts, the lower the gallbladder with cystic duct.

During fetal development, the main source of blood to the liver is the umbilical vein that transported nutrients to the fetus. The umbilical vein enters the abdomen at the navel and moves next to the free end of the falciform muscle on the bottom exterior of the liver, where it joins the sinister branch of portal vein. Ductal Aranza brings blood from the left branch of portal vein branches of the left hepatic vein and then into the lower vein so that blood from the placenta to bypass the delivery of the fetus.

Liver in the fetus develops during pregnancy and does not perform the normal function of blood purification. The activities associated with digestion, because the fetus is fed directly from the mother's bloodstream through the placenta. Releases fetal liver stem cells migrate to the thymus and fetal red blood cells and T cells after birth, the shift of stem cells in bone marrow.

Within five days after birth, the umbilical vein and ductus venosus close first, Teresa and the ligamentum venosus ligament seconds. In the case of cash or portal vein hypertension, the umbilical vein again.

Numerous liver diseases are accompanied by jaundice caused by augmented levels of bilirubin in the body. Bilirubin is the result of degradation of hemoglobin of dead red blood cells are normally removed by the liver and excreted in bile.

•  "With hepatitis, inflammation of the liver, is caused by different viruses, but also some toxic substances, autoimmune diseases and inherited conditions;

• Liver cirrhosis is the formation of fibrous tissue in the liver to kill hepatocytes, respectively. Liver cell death caused by viral hepatitis, alcohol poisoning or other toxic substances;

• With Hemochromatosis is an inherited disorder that causes iron accumulation in the body, leading to long-term liver damage;

• Benign tumors such as adenoma, "angioma" focal nodular hyperplasia.

Liver cancer as the primary tumor or carcinoma cholangiocarcinoma, or metastasis of cancer to other parts of the digestive system;

• Wilson disease is an inherited disorder that causes copper accumulation in the body;

• Primary sclerosing cholangitis, an inflammatory autoimmune disease carries bile;

• Pime biliary cirrhosis, autoimmune disease of minute rage ducts;

• Budd-Chiari syndrome or hepatic vein obstruction;

• Gilbert's syndrome, a genetic disorder of bilirubin metabolism.

There are also many pediatric liver diseases. Proper liver function can be verified by a number of specialized clinical studies, which measure the presence or absence of typical enzymes, metabolites, or substances associated with the regular activities.

Liver functions were performed liver cells to hepatocytes.

• The liver produces and secretes bile, used to emulsify fats. Part of the bile is poured directly into the duodenum, the part stored in the gallbladder.
• liver performs many functions in carbohydrate metabolism:
• gluconeogenesis or synthesis of glucose from certain amino acids, lactic acid or glycerine;
• glycogenolysis and the formation of glucose from glycogen (also occurs in the muscles);
• glycogen, or glycogen from glucose;
• destruction of insulin and other hormones;
• protein metabolism.
• Liver is also involved in lipid metabolism:
• There is a synthesis of cholesterol;
• the synthesis of triglycerides.
• hemoglobin, the liver breaks', creating metabolites that are added to bile as pigment.
• Liver break's highly toxic substances and various drugs in a development called drug metabolism. This process can lead to poisoning, when the metabolite is more toxic than its predecessor.

• The liver converts ammonia "in the bridge.
• liver serves as a repository for numerous substances, as well as glucose (as glycogen), vitamin B 12, copper and also iron.
• In the fetus until the third month, the liver is the major site of production of red blood cells are replaced in this capacity from bone marrow at 32 weeks of pregnancy.
• liver reticuloendothelial system contains highly specialized cells of the immune system as "filters" against anti carried by the portal vein system.

Currently, there is no artificial organ able to emulate all the functions of the liver. Some of them are emulated by liver dialysis, an experimental treatment for severe cases of liver failure.

Detoxification 
One of the main activities of the liver is the detoxification of the body of toxins, wastes and other harmful elements. The most important of these shares detoxifying the transformation of an ammonia presented in the blood (toxic substance derived from proteins ) ina substance tolerable at higher concentrations, the urea. The urea is then pumped back into the blood relations with other bodies. The cytologic features of hepatocytes reflect the detoxifying function of the gland. They already have an endoplasmic reticulum smooth high abundance. Quest Organelle fact, in addition to chairing the synthesis of some steroids is intensely involved in the activity of its detoxification of potentially harmful or foreign molecules (alcohol, drugs, etc.).

The four major cell types that are found in the liver are hepatocytes, stellate cells, sinusoidal endothelial cells and Kupffer cells.

Hepatocytes are the most numerous cells of the liver, represent 80% of the volume and about 60% by a number. Their shape is multifaceted, with a number of areas ranging from six to twelve, their diameter ranges from 20 to 30 microns. They are often multinucleated and tetraploid, with the number of cores that can be up to four, a large nucleolus, rough and smooth endoplasmic reticulum well developed, numerous cisternae of Golgi, ribosomes, lysosomes, mitochondria, peroxisomes. Which are both one cell types in which the organelles are more developed and presented, due to the high metabolic needs and the wide variety of tasks which they perform?

In a well-nourished body is not difficult to detect moderate amounts of glycogen and lipid vacuoles, or in the case of an overdose of iron, vacuoles or aggregates of ferritin and hemosiderin. The cytoplasm is an eosinophilic background for the large number of mitochondria but with numerous basophilic granules due to the rough endoplasmic reticulum and ribosomes. You can find lipofuscin granules of golden-brown. The pole is fitted with sine of hepatocita many long and irregular microvilli on average 0.5 microns; the surface area alone is equal to 2 / 3 of the entire cell. Two adjacent hepatocytes form their plasma membranes with the bile canaliculi and are joined by tight junctions to prevent the entry of bile into the interstices, in the rest of the cell are the most common desmosomes and gap junctions. At the level of bile canaliculi accumulating numerous exocytosis of vesicles containing precisely to secrete bile into canaliculi.

Ito or stellate cells, mesenchymal and far fewer of hepatocytes, are placed between the plates at the base of hepatocytes, and have a star-shaped or irregular. Their cytoplasm is rich in lipid vesicles containing vitamin A, and their job is to secrete the main constituent materials of the matrix, including type III collagen and reticulin. They are essential in liver regeneration following injury or surgery because they secrete growth factors responsible for good regeneration capacity of the liver. In case of injury can replace damaged hepatocytes and by the secretion of collagen and other structural proteins, forming scar tissue from the area 3 of each berry. Other substances secreted from their body contribute to homeostasis.

Sinusoidal endothelial cells are fenestrated endothelium of venous sinusoids of the liver. They have flattened, with an oval centrally located, scant cytoplasm containing numerous vesicles transcytotic, are joined by adherens junctions. The perforation between these cells is very large and combined in complex with an average diameter of 100 microns, so that blood can easily spill over the space of Disse and come into contact with the microvilli of hepatocytes.

Kupffer cells, macrophages of the liver, are derived monocytes, they are in the lumen of the venous sinusoids. Their shape is variable and irregular, with numerous protrusions typical of cells of the macrophage that extend into the lumen of the sinusoid. Their function is to remove any debris by phagocytosis in the blood flow in the liver, but may also stimulate the immune system through the secretion of numerous factors and cytokines. Remove aged or damaged red blood cells acting as a complement to the spleen (which may be substituted in case of splenectomy).

General structure
The liver is covered (except for bare triangular area on the upper surface) from the visceral peritoneum, consisting of the mesothelium, a single layer of surface cells and underlying tissue extraperitoneal. It is also completely surrounded by loose connective tissue component of the capsule of Glisson, who is as well the neurovascular bundle at the hilum out from it and trabecular connective tissue septa that penetrated the liver parenchyma, dividing it in the portal tracts. Within each area, there is a branch of the portal vein, a hepatic artery, a bile duct (portal triad) and often furthermore small lymphatic vessels and nerve branches.

The parenchyma is composed of plates instead of the complex three-dimensional structure and consist of a single layer of cells, or hepatocytes, the major liver and those that perform almost all of its metabolic functions. Each layer of hepatocytes is separated from each other by a venous sinusoid, resulting from the branching of the portal vein which runs in the portal space. It takes up space portal to a centrilobular vein. Hepatocytes do not adhere to the venous sinusoids, but are separated by a small intercellular space dilation in pathological conditions (0.2-0.5 μm), said space of Disse.

In the space of Disse contains mainly fibers of collagen type, I, III and IV and their protrude of hepatocyte the microvilli and the nerve endings. There is considerable scope for exchange between hepatocytes and sinusoidal veins or because of the greater absorption surface provided by the microvilli at the beginning, that the fenestrations present in the venous sinusoids. Among a hepatocyte and the other (on each side of the cell) are those small shower's bile canaliculi, so that each hepatocyte is almost surrounded it. The canaliculi drain into bile ducts of greater size, the canals of Hering, in turn these bile ducts of the portal triad, and these drain the bile ducts in the liver and then in the bile duct.

The ramifications of the hepatic artery are divided further into capillaries, which then convey the blood into the venous sinusoids, or the same arterial branches converge in the sinusoids, so that the hepatocytes maintain a mixed blood of the arteries and veins. Centrilobular veins unite in the veins of the higher caliber, the interlobular (placed between the liver lobules), which in turn drains into hepatic veins and those in the inferior vena cava. One of the functional units of the liver, the largest in scale, is the liver lobule.

This is a pseudo-hexagonal-shaped structure (tends to be more regular in other animals not humans) whose skeleton is represented by plates of hepatocytes separated by sinusoids resulting from venous branch portal vein. The edges are not restricted to radially expand from a vein tax centrilobular hepatic veins, but have branched structures in three dimensions and difficult to schematization. Each lobule is surrounded by thin connective tissue septa, and every "corner" opens a portal triad. Smallest functional unit of the liver lobule is the liver acinus. A berry is a section of liver parenchyma oval shape; whose axis connects two centrilobular veins and less about one side of the hexagon formed by the liver lobule. Each berry is divisible by a functional point of view into three zones.

Zone 1 is defined periportal, and is the closest to the branch of the portal vein and the terminal branches of the feeding vessels, its major axis joining the two branches portals; the child is a little depth in the parenchyma of the lobule. Zone 2, intermediate level, is a triangle that includes only the parenchyma of the lobule in its middle portion, zone 3, centrilobular vein is approaching, and it includes a commission. The berries thus assume an oval or diamond shape.

The liver is an organ attached to the digestive system from the wedge shape, shaped by its relationship with adjacent organs and muscles. It is covered by a connective capsule, known as Glisson's capsule, which protects it but does not contribute significantly to its shape. It weighs about two kgs, equivalent to 2.5% of body weight of an adult man as a medium built, in the infant liver weights for the greatest development in relation to the rest of the body can get to be 5% of total. The liver tends to reach its largest size at 18 years of age, after which its weight decreases gradually with increasing age. The liver surface is smooth and soft, reddish-brown, but in obese subjects may appear yellow, due to widespread infiltration of adipose tissue in the liver parenchyma (steatosis).

Reports
The liver is located in the further-up abdominal cavity; it occupies almost all in right hypochondria and epigastrium, going with the left lobe to occupy a part of hypochondria left, which may be more or less visible depending on the subject. Its upper surface is at the level of the 5th coast and the 10th thoracic vertebra, while the inferior-lateral summit pushes up costs at the 11th and the 2nd lumbar vertebra above Glisson's capsule and the peritoneum (except for a small triangular area) separate, it from the diaphragm, anterior-lateral and relationship of the diaphragm that separates it from the accurate pleura.  Sometimes the left lobe is related in the same way with the left pleura inferiorly by the transverse colon, the antrum of the stomach, kidney and adrenal gland, right, rear with the gallbladder, fundus of the stomach, esophagus and the inferior vena cava.

Lobi
The liver, according to the classical distinction and is divided into four lobes: right, left, square, and caudate.

The right lobe is the most voluminous organ, vaguely shaped dome that covers at least part of all the five faces of the liver. Conventionally, the falciform ligament superiorly and inferiorly venous ligament separating it from the left lobe, but now this distinction is no longer accepted.

The left lobe has a volume equal to about half of the right and is thinner, has a triangular shape.

The lobe is square on the back surface of the liver, and appears as a rectangular projection, is functionally related to the left lobe. Its boundaries are the right fossa cyst and the gallbladder, the hepatic hilum superiorly, laterally round ligament.

The caudated lobe is a projection of the rear surface of the liver, consisting of the papillary process and the caudated process, is also functionally related to the left lobe. It is bordered inferiorly by the ILO hepatic venous lateral ligament superiorly and medially from the hepatic veins from the inferior vena cava.

Faces
The surface of the liver is commonly divided into five faces: top, front, right, back and bottom. The top sides, fore and right sides are continuous with each other, and we can refer to all calling diaphragmatic surfaces of the liver.

The upper face, in the area between the further-up margin of 5° and the lower cost of the 6th, is the largest, has a pear shape and is separated from the dome of the right diaphragmatic peritoneum, an exception ' triangular area in which the two layers of the falciform ligament diverge, leading to direct contact between the diaphragm and the Board. The center and level the divergence of the falciform ligament. there is a slight depression, that impression rate. Is the anterior superior surface of right and left lobes?

The front face is convex and has a triangular shape, is at the lower edge of the area between 6 the coast of the upper 10°. It is also covered by peritoneum except for the insertion of the falciform ligament. Part of this is related to the diaphragm, which covers the front. Sometimes mild depression can be distinguished elongated, finger ribs. Forms the anteroinferior surface of the right lobe and left lobe.

The precise side is convex and in accordance with the right diaphragmatic dome, which shapes the form and separates it from the right lung. The diaphragm covers the front by the sixth to the ninth or tenth coast. It includes the right-side surface of the right lobe.

The back is broad, convex to the right but with a concavity determined by the convexity of the spine. It includes the rear surface of the right lobe of the liver and the caudate lobe. It is joined to the diaphragm by connective tissue and is a large triangular area naked. Hepatic hilum side has a vertical hole which is housed in the inferior vena cava. And below the bear, there is a small triangular depression, the imprint of the adrenal side and below it, a deep concavity which is oval rather instead the imprint failure, determined by the right kidney. Footprint kidney medially there is another slight concave oval, the duodenal impression, determined by the first portion of the duodenum. Below this there is a footprint renal semicircular depression, the colic impression, determined by the hepatic flexure.

The underside includes a rear surface of most of the left lobe and the lower half of the right lobe and the hilum and the liver lobe square. In a shallow grave postero-medial to the inferior vena cava, houses the gallbladder. On the left lobes are the footprint and the footprint of gastric esophageal (determined by abdominal section of the esophagus), two adjacent depressions. The imprint colic may sometimes be on this side.

Ligaments
The liver has several peritoneal ligaments that connect to other organs, the anterior abdominal wall and diaphragm, falciform ligament, coronary ligament, round ligament, left triangular ligament, Right triangular ligament, venous ligament, lesser omentum (hepatogastric ligament).

The falciform ligament is formed from two sheets placed on the front and top sides of the liver and is classically considered to be the divisor of its right and left lobes. Above the two layers differ and are the coronary ligament. The round ligament, which is a remnant of the left-hand umbilical vein, is less than the continuation of the falciform ligament and protrudes from the liver into the abdominal cavity, dividend, on the back surface of the organ, the left lobe by lobe square.

The coronary ligament is continued on the back surface of the leaflets of the falciform ligament. In the left lobe of the coronary ligament merges with the package left venous ligament, giving rise to the left triangular ligament, in the right lobe merges with the right package of venous ligament, giving rise to the right triangular ligament. Here also defines the bare triangular area of ​​the liver in direct contact with the diaphragm, as well as a smaller one at the left lobe.

The left triangular ligament is composed of a double layer of a peritoneum that is continuous with the falciform ligament before and after the lesser omentum. The right triangular ligament is rather a continuation of the coronary ligament.

The ligament is the residual venous anastomosis vein present during fetal life between the portal vein and the left hepatic vein. It begins in the wake of venous ligament, located on the rear surface of the liver, contrary to the falciform ligament. It divides the left lobe of the liver from the caudate lobe.

The lesser omentum or hepatogastricligament is a peritoneal fold that connects the back surface of the liver to the small curvature of the stomach (pars flaccida) and the first portion of a duodenum (pars TENS). The Pars Tensa contains within it the formation's hepatic pedicle. The hepatoduodenal ligament is to define the whole epiploic Winslow. Has a shape that is defined as "L," where the vertical line indicates the venous ligament and the horizontal to the continuation of the lesser omentum at the hilus? It continues in the right coronary ligament and left triangular ligament.

Sectors
The liver, however, is no longer divided, as it was following the procedure's macroscopic anatomical surface, in right and left lobes by the falciform ligament, but will instead be studied based on vascular, as proposed by Claude Couinaud in 1957. because they are more closely related to the physiology of the organ. A distinction is therefore, four sectors (right lateral, right medial, left medial, left lateral), each determined by a branch of the portal vein, and six slots (right portal, the main portal, umbilical, left portal, venous, Gans), or cross-cutting areas. Each sector is further divided into 1-4 segments, for a total of nine segments, which are conventionally referred to by the corresponding Roman numeral. The segments are divided based on the tertiary branches of the portal vein, hepatic artery and bile ducts that are contained in the stalks glissonian because enveloped by the sheath of Glisson. Starting from the right lobe of the liver to the left and whereas the front surface of the liver can be distinguished:

The right lateral sector, formed from segment VII superiorly and inferiorly by the VI.
The media sector right format at the top and bottom of the eighth segment V.

The left medial area, formed from the side of, I and IX segment, medial to them by the III and IV (medial to IV).

The left lateral field, formed from the second segment.

Cracks
The slots are divided into major (left main, left), which contain the hepatic veins and minor (umbilical vein, Gans), which does not contain them.

The main portal fissure is between the apex of the gall bladder and the imaginary vertical line passing through the center of the inferior vena cava. It divides the right lobe of the left lobe, the medial area from the right medial left field. It welcomes the hepatic vein media.

The left portal fissure divides the left-hand lobe of the liver in the left lateral and medial left in the field. It welcomes the left hepatic vein and extends from the falciform ligament and left triangular ligament.

The precise portal fissure divides the right lobe of the liver in the right medial and accurate lateral fields. Granting the right hepatic vein.

The umbilical fissure separates segment II from segment III in the left lobe of the liver and contains the umbilical vein in the slot, one of the two major branches of the left hepatic vein, and some branches of the hepatic left. It corresponds to the insertion of the falciform ligament.

The fissure vein is the continuation of the umbilical fissure on the lower surface of the liver and corresponds to the groove of venous ligament, then runs between the caudate lobe and segment IV.

The slot is located behind the Gans cystic fossa, below the right lobe.

Segments here are the nine segments of the liver where it is now divided. The segment corresponds to the caudate lobe, is represented only in the hinder surface of the liver. It is located posterior to segment IV. Side there is the seventh segment, distinct from the minor vena cava which runs units groove, the medial segment II, which is divided by the groove of the venous ligament. Receive It receives from the middle hepatic vein, left and right hepatic artery, drains into the inferior vena cava.

The segment II is the only range in the left side, so is the side of the whole liver. Medially and inferiorly to it is hypersegment, and is divided by the segment from the falciform ligament. It drains into It drains left hepatic vein, and in rare cases, directly into the inferior vena cava. The third segment is the side of the left-hand medial area, therefore, the gap between the umbilical and left portal fissure. Side to it is the fourth segment, the median segment II. It drains into the left hepatic vein.

The fourth segment is the lateral portion of the left medial sector, is between the main portal fissure and the umbilical slit. Medially it is the third segment, lateral segment of the V (the edge of this segment passes through the vertical axis of the gall bladder) and part of the segment, with the upper segment IX. Hepatic vein drains mainly in the media, but has smaller branches in the left hepatic vein.

The fifth segment is the lower portion of the medial right sector of the liver. It is bordered medially with the fourth segment, the side with the sixth segment, with the upper segment VIII. You crack between right portal and main portal fissure. Drains into the right hepatic vein and hepatic vein in the media.

The sixth segment forms the lower portion of the right lateral sector. It is bordered medially by the V segment, with the upper segment VII and a small portion on the lower surface of the liver with the ninth segment.

The seventh segment forms the upper portion of the right lateral sector. It is bordered medially by the anterior segment VIII, while the latter is divided by the segment from the inferior vena cava inferior with the sixth segment. His veins draining into the right hepatic vein and may reach the inferior vena cava through the right middle hepatic vein.

Segment VIII is only present on the anterior surface of the liver, is the upper portion of the right medial area of the organ. It is bordered laterally with the segment VII, with the V segment inferiorly, medially with the fourth segment. It drains into the middle hepatic vein and right hepatic vein.

The ninth segment, represented only in the rear surface of the liver, is a subdivision of the segment and represents the right side, that is next to the inferior vena cava the drains in the same vein segment lower boundary with the fourth segment VII laterally with the upper segment and the segments.

Ilo liver
The ILO is composed by a depression located on the lower surface of the liver, which is located posterior to the square lobe and anterior caudate lobe. Receive the neurovascular bundle directly to the liver and bile ducts made up primarily of two livers from the hepatic artery, the portal vein, some lymphatic vessels and nerves that make up the hepatic nerve plexus. Each beam structure is covered by the sheath of Glisson hepatobiliary, composed of unsecured connective tissue, the same one that covers the surface of the faces of the liver who accompanies each pot until the penetration in one or more liver segments. In the space between a vessel and the other is the loose connective tissue support. Just before entering the liver parenchyma, bile duct branches in the duct and precise hepatic duct in the left hepatic duct, which then penetrate the hilum, these bile ducts are more anterior ducts of the hepatic hilum. Posteromedial to the two hepatic ducts, starting in the two branches of the hepatic artery (left hepatic artery and right hepatic artery), with the right hepatic artery of a greater caliber than the left. Later, the two branches of the hepatic portal vein enter the hilum with its two branches (the left portal vein and right portal vein), the right size larger than the left all these vessels entering the hilum in supper-lateral direction. In the space between the two branches of the hepatic artery and portal vein starting in different lymphatic vessels of the small caliber, more rarely, he found someone laterally, or medially before hepatic artery numerous nerves (nerves and nerves of the left lobar right) shall run with both portal vein and hepatic artery between it and the two hepatic ducts.

Arteries
The hepatic artery is the main artery that supplies the liver. It originates from the celiac trunk, common hepatic artery, where it is called, then the front door and side passes the rear of the whole epiploic, the duodenum and superiorly by the lesser omentum. During its course issues such as its branches left gastric arteries (thick) and the gastroduodenal artery and right. At this point, it is called the proper hepatic artery following the further-up curve in front of and behind the portal vein, hepatic artery branching into left and right hepatic artery. The right hepatic artery has a sinuous course, goes to the rear to the duct common bile duct, which then emits its ramifications now the cystic artery, which descends antero-inferiorly on the gallbladder, and higher backward behind the right hepatic duct. At this point, it enters the liver parenchyma, horizontal folds and divides into two further branches, one proceeds antero-superiorly and supplying the segments, I, V, VIII, each with a branch. The other runs laterally and posteriorly and supplies arterial branches to VI, VII segment. The left hepatic artery of the lower caliber, upper back, and here enters the liver parenchyma is divided into three branches, one side for the fourth segment, a top for the third, one medial for the second. The segmental arteries are the terminal type.

Veins
The liver has two venous systems, that of the portal and hepatic veins.
The portal vein, which originates from the confluence of lien ale vein and superior mesenteric vein, dates back to the hole before and after epiploic gastric artery and hepatic bile ducts. Prior to it starting in some lymphatic vessels, lymph nodes can be found, and some nerves making up the hepatic nerve plexus. Shortly before entering the liver parenchyma is divided into left and right portal vein, with the right size larger. The left branch has a course longer and more horizontal than the right, just entered the parenchyma becomes more horizontal and emits a small branch to the posterior segment. The rest continues parallel until fork in a branch that descends anterior-inferior and divides into two stems that are directed to the medial and lateral to the third to the fourth segment. The other branch continues horizontally entering in the second segment. The right portal vein, larger and shorter, now branching into two branches, an anterior-lateral fold and divides into two stems, the upper sprays the eighth segment, the lower V, the other branch continues postero-laterally to fork in a branch than for the seventh and the sixth in a subordinate segment.

The three hepatic veins (left, middle and right) tributary of the inferior vena cava was identified as the venous system of the liver. Their course in the liver parenchyma allows you to split the liver in the fields; their peduncles allow to divide each sector into further segments. The right hepatic vein is the largest of three runs in the top exact portal fissure, inferiorly draining segments V and VI each with a stalk, the upper segments VII and VIII, and then go and lead supper-medially in the inferior vena cava. The corresponding fields are the right lateral and medial side of right. The middle hepatic vein runs in the main slot, bottom drains segments V (medial) and IV (side), the upper part VIII (medial) and again the fourth, then come out in the inferior vena cava. The corresponding fields are the right medial and left medial. A small vein, branch of the inferior vena cava, drains the individual segments. The left hepatic vein drains inferiorly (umbilical vein) segments IV (medial) and III, while the second segment is drained, the other horizontal stems. Sometimes it may issue a stalk to the fourth segment. The corresponding fields are the left medial and left lateral.

Lymph
The liver has a system composed of numerous lymphatic vessels, which are directed towards the nodal supradiaphragmatic and subdiaphragmatic. The lymphatic vessels are located generally in the space between the portal vein and hepatic artery and between the liver and bile ducts. They are classified into superficial and deep lymphatic vessels.

The superficial lymphatic vessels (located in the subserosal tissue amount) of the posterior, caudate lobe, the posterior portion of the minor face of the right lobe shall run with the inferior vena cava and pericaval draining lymph nodes, and lymph vessels of the ligament and coronary ligament right triangular flow into the thoracic duct without passing through lymph nodes. The lymphatic vessels of the front face of the lower (except the rear portion of the right lobe) and the upper draining lymph nodes in the neurovascular bundle at the hepatic hilum. The lymphatic vessels of the lower surface and the posterior portion of the left lobe paracardiac draining lymph nodes, those of the right face and right side of the upper face draining celiac lymph nodes, following the course phrenic artery.

The deep lymphatic vessels, located in the liver parenchyma, represent a complex system of small blood vessels that lead to another size increasing, until the last few in the number, tend to follow the course of the three hepatic veins, and then the inferior vena cava, draining pericaval lymph nodes. Those vessels located in the lower portion of the liver, draining vessels in size but more is in the lower door and draining lymph nodes at the hepatic hilum.

Innervation
The liver parenchyma is innervated by branches of the hepatic nerve plexus, consisting of the sympathetic and parasympathetic fibers, which enter through the hilum. Their course to accompany the ramifications of the bile ducts and hepatic artery, which provide vasomotor nerve fibers, while the hepatocytes are innervated directly. The ramifications of the parasympathetic nerve that descend along the bottom duct common bile duct, forming a plexus around the gallbladder, are mainly excitatory. Glisson's capsule is innervated by thin upper branches of the intercostal nerves.