A portal triad is a distinctive arrangement in the liver

Liver

The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

. It is a component of the hepatic lobule

Hepatic lobule

A hepatic lobule is a small division of the liver defined at the histological scale. It should not be confused with the anatomic lobes of the liver , or any of the functional lobe classification systems....

. It consists of the following five structures:

• hepatic artery
  Hepatic artery
  Hepatic artery can refer to:* Common hepatic artery * Hepatic artery proper...
  
  
• hepatic portal vein
  Hepatic portal vein
  The hepatic portal vein is not a true vein, because it does not conduct blood directly to the heart. It is a vessel in the abdominal cavity that drains blood from the gastrointestinal tract and spleen to capillary beds in the liver...
  
  
• bile duct
  Bile duct
  A bile duct is any of a number of long tube-like structures that carry bile.Bile, required for the digestion of food, is excreted by the liver into passages that carry bile toward the hepatic duct, which joins with the cystic duct to form the common bile duct, which opens into the intestine.The...
  
  
• lymphatic vessels
• branch of the vagus nerve
  Vagus nerve
  The vagus nerve , also called pneumogastric nerve or cranial nerve X, is the tenth of twelve paired cranial nerves...
  
  

The misnomer "portal triad" traditionally has included only the first three structures, and was named before lymphatic vessels were discovered in the structure. It can refer both to the largest branch of each of these vessels running inside the hepatoduodenal ligament

Hepatoduodenal ligament

The hepatoduodenal ligament is the portion of the lesser omentum extending between the porta hepatis of the liver and the superior part of the duodenum.Running inside it are the following:* hepatic artery proper* hepatic portal vein* common bile duct...

, and to the smaller branches of these vessels inside the liver.

In the smaller portal triads, the four vessels lie in a network of connective tissue

Connective tissue

"Connective tissue" is a fibrous tissue. It is one of the four traditional classes of tissues . Connective Tissue is found throughout the body.In fact the whole framework of the skeleton and the different specialized connective tissues from the crown of the head to the toes determine the form of...

 and are surrounded on all sides by hepatocyte

Hepatocyte

A hepatocyte is a cell of the main tissue of the liver. Hepatocytes make up 70-80% of the liver's cytoplasmic mass.These cells are involved in:* Protein synthesis* Protein storage* Transformation of carbohydrates...

s. The ring of hepatocytes abutting the connective tissue of the triad is called the limiting plate.