Portal circulation is a unique form of circulation that occurs at a few locations across the body when veins instead of arteries provide blood to the capillary bed.
Micro circulation is the movement of blood over a capillary bed from an arteriole to a venule. To allow for the exchange of nutrients and other biological components between the blood through circulation and the surrounding tissue, blood flow in the capillaries slows down. Only a single red blood cell may get through without deforming.
