In addition to the digestive juices that are poured into the small
intestines from the pancreas and the liver, there is a juice which
is secreted from the walls of the intestinal cells. This is called
intestinal juice or succus entericus. It is a light yellow fluid with a
strong alkaline reaction, due to the presence of sodium carbonate.
One action of the intestinal juice is to change sugar and maltose into
glucose, which is then absorbed directly into the blood.