Name: Anatomy Physiology by Elaine N. Marieb, Katja N. Hoehn
Author: Elaine N. Marieb and Katja Hoehn

In organs with rich arterial anastomoses, collateral channels can reroute blood around a blocked or cut branch, so tissue may still receive enough blood to survive. In organs like the retina, kidneys, and spleen, arteries either lack anastomoses or have poor collateral circulation, so interruption of blood flow causes the supplied cells to die.

Key points

Arterial anastomoses create collateral channels that provide alternate pathways for blood delivery.
If one arterial branch is cut or blocked by a clot, collateral channels can often supply sufficient blood to the area.
Such anastomoses are common around joints and in abdominal organs, heart, and brain, including the cerebral arterial circle.
Retina, kidneys, and spleen have arteries that either do not anastomose or have poorly developed collateral circulation.
In those organs, interruption of blood flow leads to cell death because no adequate alternate blood supply exists.

Compare the consequences of blocked arterial flow in organs with rich anastomoses versus organs like the retina or kidneys.