Which part of the nervous system innervates the lymphatic collectors?

• A. Spinal nerves of the Somatic Nervous System
• B. Cranial nerves of the Somatic Nervous System
• C. Sympathetic Branch of the Autonomic Nervous System
• D. Parasympathetic branch of the Autonomic Nervous System

Answer: (C)

Lymphatic collectors move lymph through rhythmic smooth muscle contractions, and these contractions are controlled by the autonomic nervous system. The sympathetic branch provides the innervation to these vessels, modulating their tone and pump activity to propel lymph toward the venous system. Spinal and cranial nerves of the somatic system innervate skeletal muscles, not the smooth muscle of lymphatic collectors, so they don’t regulate lymphatic flow. The parasympathetic branch isn’t the primary driver for lymphatic propulsion in this context. Therefore, the sympathetic branch of the Autonomic Nervous System is the responsible innervation.