Final answer:
The dorsal motor nucleus of the vagus nerve sends parasympathetic fibers to the heart, lungs, and upper GI tract.
Step-by-step explanation:
The dorsal motor nucleus of the vagus nerve sends parasympathetic fibers to all of the above organs. The parasympathetic output is based in the brain stem and sacral spinal cord.
Neurons from particular nuclei in the brain stem project to terminal ganglia located close to or within the wall of target effectors. These preganglionic fibers release ACh onto nicotinic receptors to excite the ganglionic neurons.
The postganglionic fibers then contact the target tissues within the organ to release ACh, which binds to muscarinic receptors to induce rest-and-digest responses.