Portal venous system

Both capillary beds and the blood vessels that connect them are considered part of the portal venous system.

The final common pathway for transport of venous blood from spleen, pancreas, gallbladder and the abdominal portion of the gastrointestinal tract[2] (with the exception of the inferior part of the anal canal and sigmoid colon) is through the hepatic portal vein.

Ascending towards the liver, the portal vein passes posterior to the superior part of the duodenum and enters the right margin of the lesser omentum.

By contrast, the ganglia of the sympathetic trunk mainly produce norepinephrine because their cells are not bathed in high concentrations of glucocorticoids.

The venous blood of the pancreatic islets is upstream from the capillary system of the exocrine pancreas via efferent ducts.

General diagram of a portal venous system, for example, this occurs in the hypophyseal portal system between the hypothalamus and the anterior pituitary gland .