Final answer:
Sympathetic pre-ganglionic cell bodies are controlled by the spinal cord, with the hypothalamus playing a central role in regulating the balance between sympathetic and parasympathetic systems.
Step-by-step explanation:
The sympathetic pre-ganglionic cell bodies receive efferent control from the spinal cord. Specifically, these preganglionic neurons in the sympathetic nervous system originate in the lateral horn of the thoracolumbar region of the spinal cord. The hypothalamus is the source of central control of autonomic function, which includes the sympathetic nervous system, and it projects to the spinal cord to regulate this balance between sympathetic and parasympathetic input to the organ systems.