List of abbreviations

Vocabulary of micros- copic anatomy specialist terms explained in English + German

Every attempt was made to provide correct information and labelling, however any liability for eventual errors or incompleteness is rejected!

dieser Seite Editor: Dr. med. H. Jastrow

Conditions of use

hepatocytes, ITO- cell, sinusoid (monkey)	hepatocytes, Kupffer- and ITO cell (monkey)	Disse's space (monkey)	hepatocyte (monkey)	Disse's space and sinusoid (monkey)	peroxisome, glycogen granules (monkey)	peroxisome (rat)

Kupffer cell (rat)	ITO-cell (rat)	bile canaliculus (monkey)	bile duct (monkey)	alpha-glycogen granules (rat)	endothelial cell of central vein + fibrocyte (rat)	cells close to bile duct (rat)

sinusoid, Disse's space, Kupffer cells (rat)*	Kupffer- and ITO cell (rat)*	bile capillary between 2 ad- jacent hepatocytes (rat)*	Macula adhaerens in between hepatocytes (rat)	reticular fibres in Disse's space (rat)	tight junction between 2 hepatocytes (rat)	hepatocyte 1 (rat)*

Disse's space, apical  cytoplasm (rat)	cytoplasm: multilam- mellar body (rat)	cytoplasm: dark Mito- chondria of crista type (rat)	cytoplasm: peroxysome (rat)	nuclear pores of a hepatocyte (rat)	Zonula occludens in between 2 hepatocytes (rat)

hepatocyte 2 (rat)	ITO cell 2 (rat)	ITO cell 3 (rat)	fenestrated sins endo- thelial cell 1 (rat)	Kupffer cell 2 (rat)*	Herring canal, endothelial cells (rat)*	hepatocyte 3 (rat)*

ITO cell 4 (rat)	fenestrated endothelial cell of a sinusoid (rat)	bile duct (rat)	Glisson's triad: arteriole + bile duct (rat)*	Kupffer cell 3 (rat)*	detail of Kupffer cell 2: large phagolysosome	granulocyte, Kupffer cell + endothelial cell (rat)*

hepatocyte 3 with excellently preserved cytoplasm (rat)	detail 1: cytoplasm with RER, SER + mitochondria	detail 2: other cyto- plasmatic region	detail 3: smooth endo- plasmic reticulum	detail 4: mitochondria and RER	detail 5: dark mito- chondrium of crista-type

ITO cell 5 (rat)	hepatocyte 4 (rat)*	detail 1: nucleus	detail 2: nucleolus	Kupffer cell 4 with phagocyted erythrocytes (rat)	Kupffer cell 5 with large phagolysosome (rat)*	Pit cell = liver specific T-lymphocyte (rat)*

mitosis of a hepatocyte (rat)	detail 1 thereof	detail 2 with spindle fibres (microtubuli) + organells	cell-to-cell contacts between hepatocytes (rat)	Zonula adhaerens between 2 hepatocytes (rat)	alpha-glycogen- granules (rat)

Liver lobule classifications:
The functional tissue of the liver, i.e. the liver parenchyme is divided in hepatical lobules (Terminologia histologica: Lobuli hepatici). From different points of view the following classifications have been established:
1. The hepatocytes are ordered in polygonal or classical hepatical lobules (Terminologia histologica: Lobuli hepatici classici; Lobuli hepatici polygonales) which show the central veins in their centres. These veins drain the blood into the branches of the liver veins. The hepatocytes are arranged in 1 - 1.5 millions polygonal, ~2 mm³ huge classical lobules in the centres of which the central veins are located in this classification. From here the hepatocytes, which are arranged in dense, parallel laminas, run like spokes of a wheel in direction of the portal fields. Regarded three-dimensionally they form six-edged columns resembling honeycombs. The 0.5 - 0.6 mm long sinusoids run in between the hepatocyte plates and slowly carry blood from the periphery to the central vein into which they drain. The hepatocyte laminas are bi-layered with bile canaliculi running at their cell membrane borders. These canaliculi start close to the central veins and lead the bile fluid from here towards the bile ductules in the periphery. Thus the bile flow is in opposite direction to blood from the centre of the lobule outwards. Classical hepatical lobules have a height of about 2 mm and their average diameter is in between of 1 - 1.3 mm. The portal areas (portal canals, portal zones; Terminologia histologica: Spatia portalia) are located at the border between three or more lobules. They consist of loose connective tissue and contain interlobular capillaries, a small lymphatic vessel as well as the portal triad (Glisson's triad; Terminologia histologica: Trias hepatica). The latter is comprised of the following closely apposed vessels: an interlobular artery (brings oxygen-rich blood from Arteria hepatica propria), an interlobular vein (carries blood from the portal vein) and a small bile duct (Ductus bilifer interlobularis; carrying bile fluid from bile ductules to the larger bile ducts finally the hepatic duct).
2. liver acinus (Terminologia histologica: Acinus hepaticus): in this classification tissue oxygen content and thus the terminal arteriols are of main interest.
3. portal lobules (Terminologia histologica: Lobuli portales). In this classification the portal canals with interlobular vein, arteries and bile ducts are regarded as centres of the lobules. The 3 closest central veins then form the border lines of the rather triangular lobules which in three dimensions form tri-edged columns.

Cell types of the liver and their functions:
A. hepatocytes, liver parenchyma cells or liver epithelial cells (Terminologia histologica: Hepatocyti) comprise the parenchyma (functional tissue) of the liver as the most important kind of cells in point of view of function. They are also called liver epithelial cells and have diameters of 20 - 30 µm and a polyhedral shape with 6 or more relatively straight edges in cross-section. Hepatocyte laminas, i.e. hepatocytic plates or hepatic trabeculae (Terminologia histologica: Laminae hepatocyticae) consist of larger arrays of directly attached hepatocytes and in the three dimensions form the hepatic muralium (Terminologia histologica: Muralium hepaticum) by attachment onto each other resulting in a network of cells of about parallel standing plates in between which the sinusoids branch. About 20 - 25% of the hepatocytes, due to their enormous metabolic activity show 2 nuclei. Such cells are more often encountered in the periportal zone I. About 50 - 60% show nuclear diameters of ~ 15 µm and are tetraploid (4-fold chromosome set) and the largest nuclei with diameters of ~20 µm are even octaploid (8-fold chromosome set) while the remaining hepatocytes have a a diploid chromosome set. Hepatocyte cytoplasm usually is rich in alpha-glycogen granules, shows many dark mitochondria of the crista-type and plenty of rough (RER)- and smooth endoplasmic reticulum (SER). In the periportal zone amount of RER is much higher than that of SER whereas close to the central veins both are about equal. Liver parenchyma cells contain about 500 peroxisomes each with diameters of 200 - 800 nm which are involved in cholesterin- and bile acid synthesis.
B. perforated endothelial cells (Terminologia histologica: Endotheliocyti perforati): The flat endothelial cells of the liver sinusoids form a discontinuous endothelium with plenty, partly over 100 nm wide, gaps lacking a basal lamina. Neighbouring endothelial cells overlap, but do NOT form tight junctions in between each other. Further, the cells show some hundreds of open transcellular pores about 100 nm in diameter which often are closely adjacent forming cribriform plates.
The stellate macrophages also known as Kupffer cells (Terminologia histologica: Macrophagocyti stellati) are large macrophages located in the lumen of sinusoids which keep their position in the streaming blood by several pseudopods which they stretch through endothelial pores into Disse's space. With their other free pseudopods they reach into the lumen trying to catch erythrocytes and other larger slow moving particles or cells.
D. ITO-cells which are also called perisinusoidal cells, fat storing cells or hepatic stellate cells (Terminologia histologica: Cellulae perisinusoidales; Cellulae accumulantes adipem) store fat and vitamin A. They are located in the perisinusoidal space (Disse's space).
E. Pit cells (hepatic natural killer cells or hepatic NK cells; Terminologia histologica: Cellulae necatoriae hepaticae) which are specialised T-lymphocytes serving for immune defence processes are also located in Disse's space.
F. Fibrocytes (Terminologia histologica: Fibrocyti) and fibroblasts (Terminologia histologica: Fibroblasti) which have a higher metabolic activity are usually only present in the loose connective tissue around the classical hepatic lobules which in humans in contrast to pigs only in case of a liver cirrhosis completely surrounds the lobules but is restricted to the portal and periportal fields under normal conditions. Only close to the central viens few fibrocytes are commonly seen.
G. Cholangiocytes (Terminologia histologica: Cholangiocyti) comprise the isoprismatic epithelial cells of bile ducts.
H. Oval cells (Terminologia histologica: Cellulae ovales) are the cuboidal epithelial cells with a characteristic single oval nucleus which comprise the epithelium of Hering canals with low differentiation which are regarded as stem cells from which cholangiocytes as well as even hepatocytes shall differentiate.

--> bile canaliculi, bile ducts and gall bladder
--> Electron microscopic atlas Overview
--> Homepage of the workshop