What is Portal lobule of liver?
The hepatic lobule is a building block of the liver tissue, consisting of a portal triad, hepatocytes arranged in linear cords between a capillary network, and a central vein. The term “hepatic lobule”, without qualification, typically refers to the classical lobule.
What structures make up a portal triad of a liver lobule?
Situated around the perimeter of the lobule are branches of the hepatic artery, hepatic portal vein and bile duct. These cluster together at the “corners” of the lobule forming what is called the portal triad.
Which structure are part of the portal area?
Liver and Pancreas Each portal triad consists of connective tissue in which are embedded a branch of the portal vein, arterioles, and interlobular bile ducts in addition to lymphatics and nerves. Portal triads may contain a small number of lymphocytes.
What is the structure of a liver lobule?
Liver Structure The hepatic lobule is the anatomic unit of the liver. In the anatomic model, liver lobules are organized into irregular polygons demarcated by connective tissue and composed of plates of hepatocytes radiating outward from the central vein to the portal triads (Figure 61-1).
How does the liver lobule work?
Each lobule is made up of numerous liver cells, called hepatocytes, that line up in radiating rows. Between each row are sinusoids. These small blood vessels diffuse oxygen and nutrients through their capillary walls into the liver cells.
What is the function of liver lobule?
These lobules are connected to small ducts (tubes) that connect with larger ducts to form the common hepatic duct. The common hepatic duct transports the bile made by the liver cells to the gallbladder and duodenum (the first part of the small intestine) via the common bile duct.
What is the function of portal triad?
Portal triads are composed of three major tubes. Branches of the hepatic artery carry oxygenated blood to the hepatocytes, while branches of the portal vein carry blood with nutrients from the small intestine.
How portal vein is formed?
The portal vein is formed by the union of the splenic vein and the superior mesenteric vein, posterior to the neck of the pancreas, at the level of L2. As it ascends towards the liver, the portal vein passes posteriorly to the superior part of the duodenum and the bile duct.
What are the 3 elements of the portal triad?
As these vessels enter the liver, their terminal branches run alongside branches of the bile ducts and course together throughout the liver parenchyma within portal triads (triad = three = hepatic artery, portal vein, bile ductule).
How big is a liver lobule?
The lobules of liver (lobuli hepatis) form the chief mass of the hepatic substance; they may be seen either on the surface of the organ, or by making a section through the gland, as small granular bodies, about the size of a millet-seed, measuring from 1 to 2.5 mm. in diameter.
What are sinusoids in liver?
Sinusoids are low pressure vascular channels that receive blood from terminal branches of the hepatic artery and portal vein at the periphery of lobules and deliver it into central veins. Sinusoids are lined with endothelial cells and flanked by plates of hepatocytes.
How many portal areas are there in the liver?
The Portal Area • Peripherally, each lobule has 3 to 6 portal areas with more fibrous connective tissue, each of which contains interlobular structures that comprise the portal triad. They include: • A venule branch of the portal vein, with blood rich in nutrients but low in O2.
How are the lobules of the liver organized?
The hepatic lobule is the anatomic unit of the liver. In the anatomic model, liver lobules are organized into irregular polygons demarcated by connective tissue and composed of plates of hepatocytes radiating outward from the central vein to the portal triads (Fig.
Where are the portal triads located in the liver?
At the vertices of the lobule are regularly distributed portal triads, containing a bile duct and a terminal branch of the hepatic artery and portal vein. Lobules are particularly easy to see in pig liver because in that species they are well deliniated by connective tissue septae that invaginate from the capsule.
What’s the difference between a portal and a lobule view?
While the classic lobule view focuses on the blood supply and hepatic mass arrangement, the portal lobule view underlines the exocrine function of the liver i.e. bile secretion.