and intestines. The aorta later divides into the left and
right common iliacs, which supply the lower
extremities (fig. 1-35).
ARTERIES OF THE LOWER EXTREM-
ITIES.The left and right common iliacs, upon
entering the thigh, become the femoral artery. At the
knee, this same vessel is named the popliteal artery
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.