Answer: Anaesthesia blocks or impairs impulse transmission which helps patients not to feel pain during surgery
Explanation: . Local anesthesia affects the neural processes usually at the nodes of Ranvier by reducing the rate at which sodium ions(which are positive) flow through the membranes. Local anesthetics blocks sodium influx into the cell membranes ensuring that the minimum threshold for transmission is not reached thereby causing no pain.
General anesthesia on the other hand opens Chloride ions(which are negative ions) channel thereby allowing chloride to flow into the cell membranes causing hyperpolarization. As the negative ions increase, this shifts the membrane potential away from the minimum threshold thereby blocking the pain during surgery.