Which of the following is a characteristic feature of sympathetic pathways in the autonomic nervous system?

• A. Use of acetylcholine as the primary neurotransmitter at the effector organ
• B. Short preganglionic and long postganglionic fibers
• C. Ganglia located close to or within target organs
• D. Originates from craniosacral regions of the spinal cord

Answer: (B)

Verified step by step guidance

1. Understand the autonomic nervous system (ANS) and its two main divisions: the sympathetic and parasympathetic systems. The sympathetic system is responsible for the 'fight or flight' response, while the parasympathetic system handles 'rest and digest' functions.
2. Recall the structural organization of sympathetic pathways. Sympathetic pathways typically have short preganglionic fibers and long postganglionic fibers. This is because the sympathetic ganglia are located near the spinal cord, not close to the target organs.
3. Compare the neurotransmitter usage in sympathetic and parasympathetic systems. In sympathetic pathways, acetylcholine is used at the preganglionic synapse, but norepinephrine is typically the neurotransmitter at the effector organ. This distinguishes it from parasympathetic pathways, which use acetylcholine at both synapses.
4. Identify the origin of sympathetic pathways. Sympathetic fibers originate from the thoracolumbar regions of the spinal cord, not the craniosacral regions. The craniosacral origin is characteristic of parasympathetic pathways.
5. Evaluate the options provided in the question. Based on the structural and functional characteristics of the sympathetic system, the correct answer is 'Short preganglionic and long postganglionic fibers,' as this is a defining feature of sympathetic pathways.