Biology: Concepts and Investigations 2nd Edition by Mariëlle Hoefnagels

Exercise 3

Dentists apply local anesthetics to deaden the pain associated with filling a cavity. These drugs block sodium channels in neurons surrounding the affected tooth. Major surgery requires general anesthetics that act on the brain, causing the patient to become unconscious and unaware of his or her surroundings. Use what you have learned about the nervous system to explain how local and general anesthetics temporarily eliminate pain.