Vagus Nerve?

[logos]

Dendrites carry afferent signals to teh soma most often, axons carry efferent signals from the soma to targets. UNless the vagus nerve has some reverse conduction, action potentials targeting efferents (the SA and AV node primarily in terms of our discussion) are carried along AXONS not DENDRITES. Just an FYI aside.

OveractiveBrain

Actually you are correct in principle, just not using "afferent" and "efferent" correctly. That is that you are correct in that in the original reply "dendrites" synapsing on the heart is technically not the correct terminology. To be a dendrite, a process has to carry information toward the nerve cell body.

I believe there is an additional complication in that these vagal efferents are preganglionic parasympathetic. Thus they should have to synapse on a post-ganglionic parasympathetic cell on the end organ (heart in this case) then a short post ganglionic fiber would synapse with the effector cell (in this case a cardiac muscle cell....but, I would hesitate to call it a NMJ because it is muscarinic).

[OzMedic]

My understanding is that NMJ only refers to the somatic nervous system i.e skeletal muscle, which is Ach activating a nicotinic receptor (as is the pre-ganglionic junctions of the ANS however it is a different type of nicotinic receptor).

[ERDoc]

The neuron without a dendrite is the pseudounipolar neuron. It has two axons with one bringing the signal in and the other bringing it out. They are usually found in the dorsal root ganglion with one axon going to the CNS and the other going to the periphery. Here is a post with some good pictures for those interested

http://faculty.washington.edu/chudler/cells.html