Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical purposes. Local anesthetics block the nerves that connect a particular body part or region to the brain, preventing the nerves from carrying pain signals to your brain. Examples include novocaine shots, which dentists use to numb the nerves in your mouth during a root canal, and epidurals, which allow for a (relatively) painless childbirth by blocking the nerves that originate at the base of the spinal cord and serve the pelvic region. For serious surgeries that require a patient to be completely unaware, doctors turn to general anesthesia. This renders patients unconscious with no perception or memory of the surgery (though pain from the surgical procedure will be apparent once you wake up). It also limits the physiological responses to surgical cuts, keeping blood pressure, stress hormone release and heart rate constant during the procedure.