Question

which set of characteristics correctly identifies a series of events in a sympathetic pathway?
thoracolumbar origin, short preganglionic fiber, ach release at ganglion, long postganglionic fiber, ne release at effector
craniosacral origin, long preganglionic fiber, ach release at ganglion, short postganglionic fiber, ach release at effector
craniosacral origin, short preganglionic fiber, ach release at ganglion, long postganglionic fiber, ach release at effector
thoracolumbar origin, long preganglionic fiber, ne release at ganglion, short postganglionic fiber, ne release at effector

Explanation:

To determine the correct set for the sympathetic pathway:

1. Origin: Sympathetic pathway originates from the thoracolumbar region (T1 - L2/L3), eliminating options with craniosacral origin (which is for parasympathetic).
2. Fiber Lengths: Preganglionic fibers in sympathetic are short, postganglionic are long.
3. Neurotransmitters: Preganglionic neurons release Acetylcholine (ACh) at the ganglion. Postganglionic neurons (most) release Norepinephrine (NE) at the effector.

Now analyze options:

• First option: thoracolumbar origin, short preganglionic, ACh at ganglion, long postganglionic, NE at effector. Matches sympathetic characteristics.
• Second option: craniosacral (parasympathetic origin), long preganglionic, short postganglionic, ACh at effector (parasympathetic traits) → incorrect.
• Third option: craniosacral origin (parasympathetic) + mixed fiber/neurotransmitter traits → incorrect.
• Fourth option: long preganglionic (opposite of sympathetic), NE at ganglion (incorrect, ACh is at ganglion) → incorrect.

Answer:

A. thoracolumbar origin, short preganglionic fiber, ACh release at ganglion, long postganglionic fiber, NE release at effector