Why is the Hepatic Portal System - Portal?

Answer 1

It is the Hepatic Portal System, because it the portal (doorway) from the digestive system to the rest of the body through the liver (hepatic means 'having to do with the liver').

The intestines absorb lots and lots of stuff from food, some of it good, some of it bad. If these substances were to directly enter your bloodstream, you'd be in pretty rough shape. The liver filters out most of the toxins and stores nutrients so they can be released into the bloodstream at a controlled rate.

Even good nutrients, like glucose, would be very hazardous if they directly entered the bloodstream, since excess levels would interfere with the osmolarity of the blood and with the metabolism of cells.

It's interesting that the entire digestive system feeds into the hepatic portal system, including the esophagus and part of the pituitary gland in your brain (since part of your pituitary was derived from the same precursor cells as your digestive system, when you were still a developing embryo). Liver damage can cause blockage of the system, and can lead to fluid build up (people with liver damage tend to have very large bellies, from abdominal fluid buildup) and leaky and fragile hepatic veins (especially in the esophagus).

Answer 2

The hepatic portal system collects nutrients from the stomach and intestine to the liver.

Answer 3

Portals are vessels that start and end in capillaries. Arteries and veins have capillaries at only one end.