Liver histology

The internal structure of the adult human liver subordinated to the architectonics of blood and bile-excreting channels. Basic structural unit of P. liver is a slice. Cells in her form hepatic beams along the radius (printing. Fig. 1 and 2). Between beams to the center cloves, where the Central Vienna, stretch sine wave. On the periphery of the slices from the gall of intercellular capillaries are formed primary biliary ducts (magdalsophia). Occupnats and together, they form at the gate P. hepatic duct, through which bile out of the liver. By Elias (N. Elias, 1949), hepatic lobule built from the system hepatic plates, converging towards the centre slices and consisting of one row of cells. Between the plates there are gaps that form a labyrinth (Fig. 5).

the structure of the liver lobules
Fig. 1-3. Schematic structure of the liver lobules (Fig. 3 Caldo): 1-ductuli biliferi; 2 - gall capillaries; 3 - v. centralis; 4 - v. sublobularis; 5 - ductus interlobularis; b-a. interlobularis; 7-v. interlobularis; 8 - magdalsophia lymphatic capillaries; 9 - perivascular nervous plexus; 10 - inflow mitakovich veins.

From the lobules are folded areas and segments of the liver associated with the branches of the portal vein and hepatic artery. Distinguish between the anterior and posterior segments in the substance of the right lobe P., medial segment, occupying the territory of the caudate and square of shares, and lateral segment corresponding to the left lobe. Each of the major segments is divided into two.
P. built from glandular epithelial tissues. Liver cells are separated gall capillaries (Fig. 6).

microscopic structure liver segments
Fig. 5. Microscopic structure liver segments (Elias); on the right - portal space for leading vein (1), limited lamina limitans; see socket (2) for the afferent venules, leading to the maze; left-maze cloves (3), gaps which are limited hepatic plates (laminae hepaticae); gaps konservirovanie to the Central space (for Central vein).

Fig. 6. Vnutritrekovye bile precapillary (1), which drain bile from vnutriposelkovykh gall capillaries (2) (Elias).

Fig. 7. Lattice (argyrophile) fiber inside hepatic lobules (silver impregnation method on Foot).

The ranks of the liver cells (beams) separated from sinusoidal perivascular spaces of the thesis, in a lumen of which facing microbikini - processes of the liver cells. Another cellular element P. - star kuperovskaya cells; it reticular cells that perform the role of endothelium vnutriposelkovykh of sinusoidal.
Layers of fibrous tissue between slices P. and parabasal connective routes are stroma liver There are a lot of collagen fibers, while in stroma segments represented mainly argyrophile reticulin fibers (Fig. 7).
Cytochemistry and ultrastructure of liver cells. Liver cell - hepatocyte - has a polygonal shape and size from 12 to 40 microns in diameter, depending on the functional state. In hepatocytes secrete sinusoidal and biliary poles. Through the first is the absorption of various substances from the blood, through the second is the secretion of bile and other substances in the intercellular gaps gall tubules. Absorbent and secretory surface of hepatocytes makes much ultramicroscopic protuberances - microvilli increasing these surfaces.
Hepatocyte limited bypass protein-lipid plasma membranes with high fermentative activity-phosphatase on biliary pole and nucleocytoplasmic - sinusoidal. The plasma membrane of hepatocytes and contains the enzyme translocase catalyzing the active transport of ions and molecules in and out of the cell. The hepatocyte cytoplasm presents a fine-grained matrix with a small electronic density and system membranes that make up a single whole with the cytoplasmic and nuclear shells. The latter is also of ducontenia, consists of proteins and lipids and surrounds the core of globular with 1 - 2 nucleoli. In the nuclear shell there are pores diameter 300-500 A. Some hepatocytes (with age, they become more) have two cores. Dual-core cell, as a rule, polyploidy. The mitoses are rare.
The organelles of hepatocytes are endoplasmic network (granular and granularly), mitochondria and apparatus (complex) Golgi. Granular endoplasmic network (elastoplast) constructed from a pair of parallel lipoprotein membranes, limiting ultra microscopic tubules. On the outer surface of these membranes are ribosomes - ribonucleoprotein granules in diameter 100-150 A. Granulema endoplasmic network is built as well, but ribosomes has not.
Mitochondria in the number of 2,000-2,500 meet in the form of threads, sticks and grain size 0.5 to 1.5 microns and are located near the nucleus and periphery of the cell. The hepatocyte mitochondria contain a huge number of enzymes and are the energy centers of the cells. Ultramicroscopic - mitochondria complex lipoprotein membrane structures engaged enzymatic transformation tricarboxylic acids, mate flow of electrons with ATP synthesis, transport of active ions in the inner space of mitochondria, as well as the synthesis of phospholipids fatty acids long chain.
The Golgi apparatus is represented by a network of bars of different thickness, which are located in different phases of secretory cycle of hepatocytes about the kernel or near the gall tubules. Ultramicroscopic it consists of granuliarnah of lipoprotein membranes, forming tubes, vials, bags and cracks. The Golgi apparatus is rich nucleocytoplasmic and other enzymes.
Complementary mechanism - perebrannye bullock - bubbles diameter 0.4 microns and less restricted to single-circuit membranes are about gleams gall tubules. They contain hydrolases and is particularly rich in acid phosphatase. Non-permanent inclusion (glycogen, fat, pigments, vitamins) in composition and quantity vary. Endogenous pigments is hemosiderin, lipofuscin, bilirubin. Exogenous pigments can be present in the hepatocyte cytoplasm in the form of salts of various metals.