The Vagus Nerve

Helpful Information about the
vital importance of slow, deep breathing:

 

https://sass.uottawa.ca/sites/sass.uottawa.ca/files/how_to_stimulate_your_vagus_nerve_for_better_mental_health_1.pdf

https://www.thecut.com/tags/vagus-nerve/

Includes an excellent diagram of the vagus nerve.