Final answer:
Acetylcholine is the neurotransmitter released by preganglionic fibers in the thoracic cavity, and it interacts with nicotinic receptors on ganglionic neurons.
Step-by-step explanation:
The neurotransmitter that is released by the preganglionic fibers in the thoracic cavity of the autonomic nervous system is acetylcholine (ACh). The receptors that respond to ACh released from these preganglionic fibers are known as nicotinic receptors, which are ligand-gated ion channels.
Their activation by ACh leads to the depolarization of the postsynaptic membrane of ganglionic neurons.Acetylcholine is the neurotransmitter released by preganglionic fibers in the thoracic cavity, and it interacts with nicotinic receptors on ganglionic neurons.