Venous System

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Blood vessels

Hospital Corpsman Revised Edition

Three principal venous systems

Venous System
Venous circulation is responsible for returning the blood to the heart after exchanges of gases, nutrients, and wastes have occurred between the blood and body cells (fig. 1-36). To return this blood to the heart for reoxygenation, the venous system begins with the merging of capillaries into venules, venules into small veins, and small veins into larger veins. The blood vessel paths of the venous system are difficult to

Figure 1-35.-Principal vessels of the arterial system.

follow, unlike the arterial system. However, the larger veins are commonly located parallel to the course taken by their counterpart in the arterial system. For instance, the renal vein parallels the renal artery, the common iliac vein parallels the common iliac artery, and so forth.