What is the Structure of the Liver?
The liver is a large, vital organ with a complex structure. It's primarily divided into lobes, but its internal organization is equally important for understanding its function.
The liver is described as a triangular, bilobed structure, with a larger right lobe and a smaller left lobe. These lobes are separated by the falciform ligament. [Source: Structure of Liver] However, some sources further subdivide the liver into four lobes: the right and left lobes, along with the smaller caudate and quadrate lobes. [Source: Liver Functions, Location, Anatomy and Disease | Columbia Surgery] A tough, fibrous layer called Glisson's capsule encloses the liver, and this is further covered by the peritoneum. [Source: Structure of Liver] The liver is located in the upper right quadrant of the abdomen, beneath the diaphragm. [Source: Liver - Wikipedia]
Microscopic Anatomy: Lobules and Portal Triads
At a microscopic level, the liver is composed of many hexagonal units called lobules. [Source: Physiology, Liver - StatPearls - NCBI Bookshelf] Each lobule's corners contain a portal triad, consisting of branches of the hepatic artery, portal vein, and bile duct. These vessels supply blood and collect bile respectively. [Source: Liver Anatomy: Overview, Gross Anatomy, Microscopic Anatomy; Liver Structure and Function - Merck Manual Professional Edition] Liver tissue is made up of many of these lobules, with numerous canals carrying blood. [Source: In brief: How does the liver work? - InformedHealth.org - NCBI] These lobules are the functional units where the liver's many processes occur. [Source: Physiology, Liver - StatPearls - NCBI Bookshelf] The liver holds approximately 13% of the body's blood supply at any given time. [Source: Liver: Anatomy and Functions | Johns Hopkins Medicine]
Summary of Liver Structure
In summary, the liver's structure is characterized by:
- Gross Anatomy: Two main lobes (right and left), sometimes further subdivided into four lobes (including caudate and quadrate), separated by the falciform ligament; enclosed by Glisson's capsule and the peritoneum.
- Microscopic Anatomy: Functional units called lobules, each containing a portal triad (hepatic artery, portal vein, bile duct).
