What effect does general anesthesia have on the patient?

General anesthesia has a significant effect on the patient by inducing complete central nervous system depression. This state is characterized by a total loss of consciousness, sensation, and reflexes, which is essential for performing surgical procedures without causing pain or distress to the patient. The depression of the central nervous system results in an absence of both voluntary and involuntary responses, ensuring that patients are entirely unaware of their environment during surgery. This profound level of sedation helps to prevent any movement or reaction to surgical stimuli, contributing to the overall safety and efficacy of the surgical procedure.

Other options describe states that are not consistent with the effects of general anesthesia. Increased awareness of surroundings would imply consciousness, which is the opposite of what general anesthesia aims to achieve. Heightened reflex response and partial arousal to painful stimuli also do not align with the intended outcomes of general anesthesia, which strives to eliminate pain perception and involuntary reactions completely.