Final answer:
The sympathetic and parasympathetic divisions of the autonomic nervous system have differing anatomies and functions. The sympathetic division broadly influences the body for fight-or-flight responses, while the parasympathetic division precisely regulates organ function during rest and digest periods.
Step-by-step explanation:
Comparing the Anatomy of the Sympathetic and Parasympathetic Divisions
The autonomic nervous system is divided into the sympathetic and parasympathetic divisions, which have distinct anatomical features and functions. The sympathetic division is characterized by its wide-reaching influence, as its preganglionic neurons can connect to multiple targets, enabling a broad systemic response during emergency 'fight or flight' situations. On the other hand, the parasympathetic division, often referred to as the 'rest and digest' system, features long preganglionic fibers that connect to terminal ganglia, which are located close to or within the effector organs, resulting in a more localized and specific response.
The anatomy of the sympathetic division has its preganglionic neurons emerging from the thoracolumbar region of the spinal cord. These neurons project to a network of ganglia, including the chain ganglia adjacent to the spinal column and the collateral ganglia, which are more distant. Through a series of branching axons, a single preganglionic neuron can influence multiple organs, reflecting the system's need for a rapid, coordinated response to stress.
In contrast, the parasympathetic division comprises preganglionic neurons that originate in the brainstem and sacral spinal cord. The axons from these neurons are longer and they synapse on ganglia that are very close to, or within, the target organs, aptly named terminal or intramural ganglia. This close proximity allows the postganglionic fibers to be short, facilitating a quick response in regulating the activities of the organ with minimal delay.