Visceral Sensory Neurons and Referred Pain

Now we will cover the visceral sensory neurons which have nothing to do with the autonomic nervous system and nothing to do with motor-related-stuff which we talked about before this.

These are the neurons that monitor stretching, temperature, chemical changes and irritation.  The cerebral cortex in the brain interprets these sensations as things such as hunger, fullness, pain, nausea, gas, cramping, etc.

The cell bodies are located in the dorsal root ganglia and the fibers travel together with the autonomic nervous system.  Since it piggybacks the autonomic nervous system, we get something called referred pain.  For example, pain from the heart can be perceived on the left shoulder and arm.  An ice-cream headache, also known as brain freeze, is another example of referred pain.  When something very cold touches the roof of the mouth (palate), the vagus and trigeminal nerves respond by causing rapid constriction and swelling of capillaries in the sinuses, “referring” the pain from the roof of the mouth to the head.

Any organ that is having an issue will create sensations of discomfort in the body where the skin is innervated by the same spinal segments.  One possible reason for this is because the ANS and spinal nerves may travel together and be misinterpreted by the cerebral cortex.  Another reason for this is that the reflexive vasoconstriction of capillaries affects and involves the dermatomes.

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Painting by Michael Reedy

The Basics. Start here. This is your Foundation.


The Autonomic Nervous System

Specialized Systems