Phantom Limb Pain: This is pain experienced in a "limb" that has been amputated. Amputees sometimes will describe pain in a limb that no longer exists.
Referred Pain: When pain originating from one part of the body is felt in another part of the body. This occurrence is usually due to the two body parts sharing or overlapping neuron pathways. E.g. sometimes when people have a heart attack, they don't feel pain around their heart, but in their left arm.
Vagal Center of the Brain: The vagal center of the brain is responsible for keeping track of what is going on in the body and "looks out" for the body when something is wrong. E.g. a psychiatric patient ate a handful of hairpins (aka bobby pins). Her doctors started panicking, thinking that her intestines and stomach would become punctured in a manner of minutes. The surgeon (who she was immediately rushed too) was relatively calm despite her state and ordered X-Rays to be taken. When the X-Rays were developed, the hair pins were visible, and to her doctors' surprise, they were all lying flat, working their way through the intestinal tract in a orderly and linear fashion. She never needed surgery as she simply excreted the hair pins out of her body. The vagal center of the brain would have kept her intestinal tract moving a long as normal and prevented the pins from getting tossed around and pricking the gastrointestinal tract lining.
Hypokalemia: This is a condition when you don't have enough potassium in the body. The symptoms associated with this condition are similar to Alzheimer's (I talked about this awhile back on my blog). One of my classmate's grandmother was experiencing Alzheimer's-like symptoms for quite some time, but after my classmate learned about hypokalemia, she recommended that her grandmother eat more bananas. I am happy to report that today her grandmother is symptom-free!