Final answer:
The autonomic nervous system differs from the somatic nervous system by having a two-step efferent pathway consisting of preganglionic and postganglionic neurons, instead of a single motor neuron.
Step-by-step explanation:
The autonomic nervous system, in contrast to the somatic nervous system, stimulates its effector cells. The somatic nervous system is associated with activities traditionally thought of as conscious or voluntary and is involved in the relay of sensory and motor information to and from the CNS. The autonomic nervous system, on the other hand, regulates organ systems through circuits that resemble the reflexes described in the somatic nervous system.
In contrast to the somatic nervous system, the autonomic nervous system has two efferent neurons in its pathway. The autonomic nervous system controls involuntary actions and targets tissues such as cardiac and smooth muscle, as well as glandular tissue. It organizes its responses through a two-step efferent pathway: the first step involves the preganglionic fiber projecting from the CNS to a ganglion, and the second step involves the postganglionic fiber projecting to the target effector. In contrast, the somatic nervous system directly projects from the CNS to skeletal muscles using a single motor neuron.