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26) The sympathetic and parasympathetic nervous systems differ by the following feature:

A. the location of their ganglia in the organism

B. one has only myelinated axons, while the other only has unmyelinated axons

C. the preganglionic neuron of one system is inside the CNS, while that of the other system is outside the CNS

D. one has a two-neuron chain from the CNS to the effector organs, while the other has a single efferent neuron.

1 Answer

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Final answer:

The sympathetic and parasympathetic nervous systems differ by the location of their ganglia: the sympathetic has ganglia next to the spinal cord, while the parasympathetic has ganglia near or inside the target organs. Both have myelinated preganglionic and unmyelinated postganglionic axons, and both include a two-neuron chain, so these are not distinguishing features.

Step-by-step explanation:

The sympathetic and parasympathetic nervous systems are two arms of the autonomic nervous system, each with a different role in body function regulation. Both systems feature a two-neuron chain from the CNS (Central Nervous System) to the target effector organs, but they differ in several ways, such as the location of their ganglia and the relative lengths of the preganglionic and postganglionic axons.

Option A states the systems differ by the location of their ganglia. In the sympathetic division, the ganglia lie in a chain next to the spinal cord. In contrast, in the parasympathetic division, the ganglia are located close to or within the walls of the target organs. So, this is one difference between them.

Regarding option B, both systems have myelinated preganglionic axons and unmyelinated postganglionic axons, so this is not a distinguishing feature. Option C is incorrect since the preganglionic neurons of both systems are within the CNS. Lastly, for option D, both systems have a two-neuron chain: the preganglionic neuron and the postganglionic neuron, so it is not a differentiating feature either.

The sympathetic division prepares the body for a "fight or flight" response, while the parasympathetic division governs the "rest and digest" state. Both systems use acetylcholine to activate their postganglionic neurons, but the sympathetic system uses norepinephrine on the target organ, whereas the parasympathetic system typically uses acetylcholine or sometimes nitric oxide.

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