“The vagus nerve is the longest and most complicated of the brain’s 12 pairs of cranial nerves. Cranial nerves send and receive information from the brain’s surface to tissues and organs throughout the body. The word “vagus” is derived from the Latin word “wandering” because the vagus nerve travels all throughout the body.
The vagus nerve is a mixed nerve that is made of 20% “efferent” fibers (fibers that send signals from the brain to the body) and 80% “afferent” (sensory) fibers (fibers that carry information from the body to the brain).
With all of this information, it is able to control many functions of the body both in the sympathetic (fight or flight responses such as increased heart rate) and parasympathetic (resting actions such as digestion) systems. It is the biggest component of a circuit that connects our brain to our neck, heart, lungs, and abdomen. Speech, digestion, taste, breathing… It’s almost unnerving how much this one nerve is responsible for…”