Final answer:
The deep inguinal nodes drain lymph from the lower abdomen, pelvis, and lower limbs, and form part of the larger lymphatic system including the thoracic duct and cisterna chyli.
Step-by-step explanation:
The deep inguinal nodes have a specific role in the lymphatic system within the human body. They are responsible for draining lymph from several regions. Specifically, the deep inguinal nodes primarily drain lymph from the lower abdomen, the pelvis, and the lower limbs, as well as directly receiving lymph from the deep areas of the lower limb. This is part of the larger network that includes the thoracic duct and the cisterna chyli, with the thoracic duct draining into the left subclavian vein and the cisterna chyli collecting lymph from various trunks.