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Dr. P here.

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I just want to talk a little bit about the function of the

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vagal nuclei at the level of the medulla oblongata.

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There's actually five of them.

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Some books say four,

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but five is probably the right number.

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And there's a lot of function of the vagus nerve,

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as you've heard. There's also a pharyngeal nerve,

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the superior laryngeal nerve.

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There's superior cervical cardiac branches,

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inferior cardiac branches, and the recurrent laryngeal nerve.

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So a lot of laryngeal function is happening

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on behalf of the vagus nerve.

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Now, let's look at those five nuclei.

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We've got the dorsal sensory nucleus, which is a

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little more medial and posterior. Right there.

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Then just behind it is the round nucleus.

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And then the third one is the nucleus of the solitary tract.

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And that one is a little more lateral.

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They kind of form a triangle right here.

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And some of these are going to contribute

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to nine, as well as ten.

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Then we get into two of the motor contributors.

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We've got the nucleus ambiguus.

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This slightly off-midline right here,

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maybe a little further back than that.

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And then we've got the second one,

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which is the nucleus of the solitary tract,

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which lies just in front of this little triad here and

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sits a little more medial than the nucleus of the solitary tract.

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So, these five participate together

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and the vagus nerve includes axons,

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which emerge or converge from all five of these nuclei.

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Now, the dorsal nucleus sends parasympathetics

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to the viscera, especially the intestines.

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The nucleus ambiguus,

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which is right here,

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gives rise to the branchial efferent motor fibers of the

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vagus nerve and preganglionic parasympathetic neurons,

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then innervate the heart. Pretty darn important.

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Then the solitary nucleus, which receives afferent

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taste information and primary afferents

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from the visceral organs,

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aand the solitary nucleus is going to be right here.

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And then finally, one that we haven't discussed,

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one you can kind of add on to these five,

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the spinal trigeminal nucleus.

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I'm not going to draw it.

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It receives information about deep, crude touch,

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pain and temperature of the outer ear,

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the dura of the posterior cranial fossa

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and mucosa of the larynx.

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And if you want to see more about that nucleus,

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you can go to the discussion of nerve number five.

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That concludes our discussion of the

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nuclear function for the vagus nerve.

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There are at least five,

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maybe even six nuclei that are participating.

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Dr. P out.