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Historical perspectives

 

Hooke (1600-1700) early microscopic observations – 1665 observed “globules” which were either the cells themselves or other artefacts or parts of tissues or cells Grewe (1600-1700) early microscopic observations similar to Hooke Lister (1830) improved microscope improved microscopic observations Purkinje (1838) identified nuclii in liver cells and established the appearance of the liver cell Minot (1900-2000 AD) distinguished the sinusoid from the capillary circulation Beckmann in 1859 noted “spindle shaped or with several processes” with “black pigment” prior to the observations of Kupffer Kupffer (1800-1900 AD) Kupffer stained the liver with gold chloride he identified this stellate cell which he thought was external to the sinusoid

 

liver lobule
 42646b03 liver liver lobule hepatic lobule vein IVC gallbladder bile duct hepatic artery portal vein normal anatomy art Courtesy Ashley Davidoff

 (Image courtesy of Ashley Davidoff M.D.)

the liver lobule is a structural and functional unit of the liver structurally characterised by plates of parenchyma separated by sinusoids placed in radial fashion around a central vein surrounded by portal triads and supported by connective tissue functionally characterised to act as a metabolic unit to process mesenteric blood and to directly transport the procesed blood into the venous circulation multifunctional in metabolism synthesis production storage transport protection part of subsegment segment lobe giving rise to liver plates sinusoids space of Disse common diseases include fatty change, hepatitis, cirrhosis requires microscopc analysis medical therapy

The parts of the lobule include plates or cords of parenchyma sinusoids portal triads central vein connective tissue divided into three zones, zone 1 closest to hepatic artery and portal vein zone 2 intermediate zone 3 abutting the terminal hepatic venule

The parenchyma is the glandular epithelium formed into structurally characterised by plates or cords radially arranged separated by hepatic sinusoids making up portal lobule bounded by portal triads

The Cells

Cells of the liver hepatocytes dominate Kupffer cells lipocytes are found within the space of Disse epithelia of the bile ducts vessels.  hepatocytes are the major cellular component of the liver comprising approximately 70% of the liver by volume. structurally characterised by their large size and the absence of a basement membrane functionally characterised by their remarkable metabolic and regenerative capability part of liver plate lobule made up of nucleus cytoplasm diseases infection, fatty change, malignancy diagnosis by microscopy and electron microscopy treatment medical

The liver  is a compound tubular serous gland structural unit is a lobule tubules are replaced by cellular plates that branch and anastomose alongside and in parallel with a vascular system size each lobule measures 1-2mm shape hexagon position within the parenchyma character malleable growth tremendous regenerative capacity parts plates of liver cells. (cords) sinusoids space of Disse central venule capsule incompletelyseparates lobules and Glisson’s capsule surrounds the portal triad support reticular network to sinusoids and Glissons capsule connections direct through incomplete capsule to other lobules sinusoids space of Disse to lymphatics central vein to systemic venous system bile ducts to digestive tract blood supply portal venous and hepatic artery via a common sinusoid nerve supply sympathetic parasympathetic ducts bile ductules venous drainage central venule, which drains into a sublobular vein. relations mostly to other lobules

The Cell

The cell

The cell is the building block of all biological structure.  In this image a few polygonal cells of the liver are attached together.  Each cell has a central dark nucleus which is embedded in a pinkish cytoplasm. The nucleus takes up approximately 1/5 to 1/6 of the volume of the cell.  (Image courtesy of Barbara Banner M.D.) 13440

The Tissue

Cells Align and Combine – Sinusoids – Shapes – New Unit – Tissue

The cells of the liver are organized in cords and plates and are organized like spokes of a wheel  around the central vein. The plates and cords are lined by the sinusoids which are the channels which carry blood to the liver.  Just below the sinusoids, between the wall of the sinusoid and the capsule of the liver there is a space called the space of Disse which carries the lymphatic fluid of the liver.   (Image courtesy

Tissue Units

Tissue Aligns and Combines – Shapes – New Unit – Lobule

The sinusoids and hepatic cords combine to form a liver lobule which is a functional and structural unit of the liver.  At the center of the lobule is the central vein from which emanate many cords of liver tissue.  At the periphery of the lobule there are 4-5 groups of portal triads consisting of distal branches of the portal vein (dark blue), hepatic artery (red) and biliary radicle (green).  They create the border of the lobule.

(Image courtesy of Ashley Davidoff M.D.) 13009 W

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Lobules
There are a multiplicity of lobules, each with a central vein and each delivering the “goods” to venules, which collectively join to form the hepatic veins and then into the IVC. Destination? The heart, from where it will be distributed to the body wide system. (Image courtesy of Ashley Davidoff M.D.)

 

The blood vessels

Venules

The central vein is a small vein structurally characterised by its central position in the lobule of the liver functionally characterised by contribution to the larger whole but being the origin of the hepatic venous system that transports metabolically rich products to the rest of the body part of hepatic venous system made up from terminal branches of the sinusoids common diseases include congestion clinical presentation pain if capsule involved diagnostic studies include right heart catheterization for pressure eavaluation treatment is commonly by medical

Biliary radicles

 Bile canaliculus is a secretory tubule. or secretory ductule. It is structurally characterised by its position midway between two liver cells. It is functionally characterised as a transport system of bile from the cell to the major biliary ducts.

The space of Disse

Disse’s space lies between the sinusoidal lining and hepatic-cell surfaces. Formed elements of the blood are excluded from the space of Disse

The capsule

The capsule that surrounds the portal triad structurally characterized being the intrahepatic extension of the liver capsule consisting of serosal outer and fibroelastic inner capsule. It also forms a loose capsule around the liver lobule. Functionally characterised as a support and protective barrier for the portal triad and the liver lobule serving to support the fine reticular network within the lobule disease from the peritoneal cavity may spread within the portal triad within the lymphatics, or within its spaces.

Applied

Alcoholic cirrhosis is a chronic inflammatory disorder of the liver caused by chronic ingestion of alcohol resulting in a scarred poorly functioning liver local change with loss of liver cells chronic inflammation of the liver and systemic signs of chronic inflammation characterised by regenerative nodules fibrosis of the liver of the micronodular type

Normal liver above and the cirrhotic liver below
 This drawing of the smooth surfaced normal liver and the nodular liver of micronodular cirrhossis below (Image courtesy of Ashley Davidoff M.D.)  42648b01

Micronodules of cirrhosis

Micronodules of alcoholic cirrhosis
02114b01 liver hepatic cirrhosis micronodular grosspathology Courtesy Barbara Banner MD

Early micronodules – cirrhosis
02191 liver hepatic fibrosis nodules fatty change steatosis early cirrhosis histopathology Courtesy Barbara Banner MD

Cirrhosis – micronodules with bridging fibrosis
00375 liver hepatic cirrhosis fx fibrosis fx nodules fx bridging between the triads histopathology Courtesy Barbara Banner

Cirrhosis bridging fibrosis
00376 liver hepatic cirrhosis fx fibrosis fx nodules fx bridging between the triads portal triad hepatic artery portal vein bile duct histopathology Courtesy Barbara Banner MD

 

 

Cardiac Congestion

cardiac cirrhosis is a chronic circulatory disorder of the liver caused by chronic right sided heart failure resulting in chronic congestion and subsequent fibrosis of the liver characterised by fibrotic process and regenerative nodules

 

Nutmeg liver – a sign of cardiac congestion
00419b01 liver fx nutmeg liver hepatic congestion dx chronic passive congestion CHF congestive heart failure histopathology Courtesy Ashley Davidoff MD

Nutmeg liver – congestive pattern with metastasis
00414 metastasis liver fx nutmeg liver hepatic congestion dx chronic passive congestion CHF congestive heart failure grosspathology Courtesy Ashley Davidoff MD

Histopathology of the nutmeg liver
02161 liver fx nutmeg liver hepatic congestion dx chronic passive congestion CHF congestive heart failure histopathology Courtesy Ashley Davidoff MD

Nutmeg liver –  high power
00420 liver fx nutmeg liver hepatic congestion dx chronic passive congestion CHF congestive heart failure histopathology Courtesy Ashley Davidoff MD

Global Cardiomegaly – CHF
00423 TR CHF heart cardiac RA RV LV fx enlarged dx CHF CTscan Courtesy Ashley Davidoff MD

 

Hepatic congestion due toi CHF
00422 liver periportal tracking IVC fx distened fx enlarged fx heterogeneous TR CHF acute cardiac failure CTscan Courtesy Ashley Davidoff MD

Gallbladder edema secondary to liver congestion
00425 gallbladder wall fx edema dx CHF liver heart cardiac dx CHF liver CHF acute cardiac failure CTscan Courtesy Ashley Davidoff MD