Translations:Blutgefäße/4/en

The walls of the larger arteries must also be nourished, therefore small arteries are built into the outer wall, which take over the nourishment and come from the closer environment. Veins and lymphatic vessels have valves from intimate pockets that protrude into the lumen as protuberances. They form valves and direct the blood stream or lymph flow to the center.