Portal tract

Yoneyama H, Matsuno K, Zhang Y, et al. Regulation by chemokines of circulating dendritic cell precursors, and the formation of portal tract-associated lymphoid tissue, in a granulomatous liver disease. J Exp Med 2(X)I I93(I) 35M9. 

The presence of protein-hydropic degeneration (Fig. 13a), punctuate infiltration and necrosis, reaction of hepatic macrophages (Fig. 13b), nuclear polimorphysm (Fig. 13c), inflammatory infiltration of portal tracts and perivenular infiltration (Fig. 13d) were considered in the assessment of morphological alterations in the liver of the mice. 

Microscopic investigation of the mice from group I revealed the presence of vessel congestion, small numerous intralobular and perivenular infiltrates, moderate focal protein-hydropic degeneration combined with polymorphism of hepatocyte nuclei and inconstant lymphoid infiltration of portal tracts. Marked activation of histiomacrophage elements — hepatic macrophages must be emphasized. Homotypic moderate inflammatory alterations remained in the liver on Days 3, 5, 7 and 10. The presence of inflammatory mononuclear infiltration in the walls of central veins, typical for a viral infection, reflects a massive lesion of the vascular... 

Classically the liver has been divided into hexagonal lobules centred around the terminal hepatic venules. Blood enters the liver through the portal tracts that are situated at the corners of the hexagon. The portal tracts are triads of a portal vein, an hepatic artery, and a common hepatic bile duct. The vast expanse of hepatic tissue, mostly consisting of parenchymal cells (PC) or hepatocytes, is serviced via terminal branches of the portal vein and hepatic artery, which enters the tissue at intervals. The hepatocytes are organized into cords of cells radially disposed about the central hepatic venule. Between these cords are vascular sinusoids that transport the blood to the central hepatic venules. The blood is collected through the hepatic venules into the hepatic vein which exits the liver into the inferior vena cava (Figure 4.1). 

The bile canaliculi form a network, which feed into ductules, which become bile ducts (Fig. 6.3). The structural and functional unit of the liver is the lobule, which is usually described in terms of the hepatic acinus (Fig. 6.5), based on the microcirculation in the lobule. When the lobule is considered in structural terms, it may be described as either a classical or a portal lobule (see "Glossary"). The acinus comprises a unit bounded by two portal tracts and terminal hepatic or central venules, where a portal tract is composed of a portal venule, bile ductile, and hepatic arteriole (Fig. 6.5). Blood flows from the portal tract toward the central... 

Figure 6.5 Schematic representation of a hepatic acinus. PT represents the portal tract, consisting of branches of the portal vein and hepatic artery and a bile duct. CV represents a branch of the central vein. The areas 1, 2, and 3 represent the various zones draining the terminal afferent vessel. Source Adapted from Ref. 5.

Indicate which of the following are true The area around the portal tract in the liver is... 

There are only a few reports of hyperacute rejection after liver transplantation. This may be due to the ability of the Kupffer cells to remove cytotoxic antibodies formed against the graft because of their reticuloendothelial function. Acute rejection is the more common form of rejection, which is manifested within 7-10 days after liver transplantation and exhibits symptoms of fever, malaise, pain, tachycardia and hepatomegaly. Mental disorientation in patients has also been reported during acute rejection. Liver biopsy is performed to confirm acute rejection that is generally mild in nature, and lymphocytic infiltration is observed in the portal tracts under the endothelium of the sinusoids. 

Approximately 30% of liver cells are nonparenchymal cells. Cell types located in the interlobular portal tracts include bile duct epithelial cells and connective tissue fibroblasts. Those located within the lobule interior are the rare fixed, natural killer lymphocytes (pit cells) and the more abundant endothelial cells lining the sinusoids, Kupffer cells, and stellate cells (also known as fat-storing or Ito cells). The recent... 

A 44-year-old woman developed weakness with abnormal liver function tests (aspartate transaminase 661 IU/1) about 6 months after starting to take venlafaxine 150 mg/day. Biopsy showed confluent necrosis in zone 3, with unaffected portal tracts. No other cause for the hepatitis could be found. The clinical and biochemical features resolved within 12 weeks of withdrawal of venlafaxine. 

Although the classic lobular model describes the microscopic appearance of the liver well, a better way to understand how the liver functions is to subdivide it into regions of hepatocytes irrigated by a single portal tract - an area referred to as the hepatic acinus. 

Blood emerging from the portal tract filters through the network of sinusoidal channels that separate rows of hepatocytes on its way towards the central vein. The hepatocytes within the acinus can be subdivided into three zones according to their distance from the portal venule. Cells in close proximity to the portal triad are the first to receive the nutrient- and oxygen-rich blood, and are consequently most... 

The liver contains two forms of endothelium conventional vascular endothelium, which is mainly localised around the portal tracts and within large vessels, and a specialised endothelium found within the... 

Biopsy results, where available, are invaluable. They may have been taken to help diagnose a disease or to give an indication of its progression. Either way, they enable you to differentiate between a mild hepatitis with an ALT of 100 and cirrhosis with a similar transaminase level. This is very helpful in determining whether or not hepatocyte function is likely to be impaired. It may also demonstrate poor biliary canaliculi or portal tracts which may result in defective bile or blood flow. 

Peliosis hepatis consists of a focal dilatation of the portal tract sinusoids. The condition is associated with contraceptive-induced hepatic tumours and can occasionally develop in isolation [13]. 

The term stroma comprises the interstitial connective tissue of an organ. In the liver, four types of tissue structure are differentiated (7.) capsule of the liver, (2.) perivascular connective tissue, (S.) Glisson s portal tract, and (4.) reticular network. 

The perivascular fibrous capsule (R Glisson, 1654) commences in the hepatic porta as a tree-like branching framework of connective tissue surrounding the interlobular vessels. It also surrounds the central hepatic vein and its small tributaries, which are joined to the parenchyma by radial fibres as well as being established in the portal tracts. This prevents a suction-induced collapse of the venous vessels as a result of respiration-dependent negative pressure in the pleural cavity. The perivascular connective tissue, known as Glisson s capsule, extends fine secondary trabeculae into the parenchyma. They contain the intralobular biliary, lymphatic and blood capillaries. 

In the portal tract (= Glisson s triangle, portal field) (E Glisson, 1659), the perivascular connective tissue with its enclosed (and protected) radicles of the portal veins, the hepatic arterioles, bile ducts, lymph vessels and nerve fibres terminates in the connective tissue covering of the... 

Fig. 2.13 Diagram of the classic hepatic lobule (I), the portal vein lobule (II) and the hepatic acinus (III) CV = central vein ( ), P = portal tract ( ). Flow direction venous blood (= blue arrow), arterial blood (= red arrow) and bile (= green arrow), with the microcirculatory acinus zones 1, 2, 3. (cf. W Ekataksin et af, 1992 the microvascular unit is regarded as an area in which all hver cells receive blood from a common terminal vessel)...

Fig. 21.5 Cholesterol ester storage disease (CESD). Micro-/macro-vesicular fat droplets in hepatocytes and foam cells in a portal tract (Sudan III)...

In persistent confluent and bridging necrosis, the development of correspondingly located fibrotic septa can be observed. Portoportal septa connect neighbouring portal tracts, such as in progressive piecemeal necrosis and in... 

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