Final answer:
The autonomic nervous system serves as the relay between the CNS and the internal organs. It controls the organs largely without conscious control and maintains their optimal functioning.
Step-by-step explanation:
The autonomic nervous system serves as the relay between the CNS and the internal organs. It controls the lungs, heart, smooth muscle, and exocrine and endocrine glands. The autonomic nervous system controls these organs largely without conscious control and can continuously monitor their conditions and implement changes as needed. There are two divisions of the autonomic nervous system, the sympathetic and parasympathetic, which often have opposing effects.