Liver histology

00:00 / 00:00

Questions

USMLE® Step 1 style questions USMLE

of complete

A researcher is studying the histology of liver parenchyma. Under histological examination, the liver parenchyma is divided into hexagonal hepatic lobules containing the central vein in the center and the portal triad at the periphery. Each hepatic lobule is divided into three different zones. The circled zone in the picture is most susceptible to which of the following injuries?  


Transcript

Watch video only

The liver is the largest internal organ in the body and weighs about 1.5 kg.

It’s surrounded by a capsule of fibrous connective tissue called Glisson’s capsule.

If we look at the liver from an inferior view, which is a view from the bottom of the liver, we can see that the liver is divided into a large left lobe and right lobe, as well as two smaller lobes, called the quadrate and caudate lobes.

The liver parenchyma or functional tissue of the liver is organized into thousands of hepatic lobules, which have a dual blood supply that comes from terminal branches of the hepatic portal vein and hepatic artery.

The blood then flows through sinusoids surrounded by hepatocytes before draining into the lobule’s central vein.

Hepatocytes are the main functional cells of the liver that perform a large variety of functions, including the production of bile, a number of plasma proteins, and non-essential amino acids; the metabolism of fat, carbohydrate, and protein; the storage of glucose, vitamins, and iron; and the breakdown or detoxification of metabolic waste products, drugs, and toxins.

At lower magnification, the hexagonal shape of the hepatic lobules can be identified by their slightly darker edges and the prominent central veins in the center of each lobule.

The portal triad consists of a bile ductule, portal venule, and arteriole.

After identifying the lobule, it can be easier to locate portal triads in an image since they’re typically located at the corners of the lobules.

If we take a closer look at just one portal triad, we can more easily identify the portal venule by its large diameter and thin walls compared to the arteriole, which has a much smaller diameter and thicker walls.

Summary

The liver consists of thousands of hepatic lobules, which on microscopic examination are identified by their prominent central vein, as well as a slightly pale central portion of the lobule compared to the edges of the lobules. On corners of lobules lie portal triads, each containing a portal venule, hepatic arteriole, and bile duct. Venules can be identified by their large lumen and thin wall, as opposed to arterioles that have a thicker wall and a smaller diameter. The bile duct is identified by its simple cuboidal epithelium. The main cells of the liver parenchyma are hepatocytes. These are large polygonal cells with eosinophilic cytoplasm and basophilic nuclei.

Elsevier

Copyright © 2024 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.

RELX