Liver: Definition, Functions & Structure

Instructor: John Williams
The liver is a vital organ that is responsible for many of the processes that keep us alive. This lesson will discuss the key functions of the liver, its location in the body, and the diseases that can affect it.


The human body is a fascinating structure, composed of many different parts working together for the purpose of keeping us alive. Within the human body are multiple organs, which are large structures designed to perform certain functions. Many of the organs in the body are familiar to most people. The heart, for example, is used to pump blood throughout the body. The lungs are used to breathe in oxygen and remove carbon dioxide.

However, one of the most important organs in the body is also one of the least understood. It is an organ that is vital for digestion. It is an organ that protects us from harmful substances. It is one of the organs that we cannot live without. That organ is the liver, and in this article, we will take a look at this valuable part of our bodies.

Location of the Liver

The liver is located superolateral (above and to the side) of the stomach. It is found in the abdominal cavity of the body, which is where many of the internal organs reside, and is inferior to (below) the lungs.

Characteristics of the Liver

The adult liver weighs between 3 and 4 pounds. It is the largest internal organ in the body, and is second to the skin as the largest organ overall. It has a rubbery texture and is reddish-brown in color. One of the most unique characteristics of the liver is that it has the ability to regenerate (re-grow) different sections of itself in the event of damage in some cases.

The Liver (shown in green)

Shape and Sections

The liver has a triangular shape, and is divided into four lobes. The left and right anatomical lobes are visible when viewing the liver from the front, while the quadrate and caudate lobes are visible when viewed from the underside. These lobes are divided further into smaller functional sections, called lobules. These lobules have various functions, and contribute to the processes that are described below.

A Schematic of the Liver
liver sections

Functions of the Liver

The liver has several major functions in the body. First, the liver is responsible for producing enzymes and solutions necessary for digestion. This includes the production of bile, which helps with the breakdown of fat from our food. The liver is also responsible for the storage of sugars for energy use. Glucose, a simple sugar used by the body for energy, is stored as glycogen in the liver until needed. During emergency situations, our bodies will tap into the stored glucose to provide additional energy for survival.

Another major function of the liver is to detoxify and remove harmful substances in the bloodstream. Drinking alcohol, for example, is poisonous to the human body. (You probably wouldn't be able to tell it based on how much we, as humans, consume it.) The liver is responsible for processing alcohol so that it does not cause harm to the rest of our bodies. Additionally, the liver will also break down and process other drugs that enter our system, including medications and recreational drugs.

Other functions of the liver include:

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