Final answer:
Local anesthetics such as lidocaine and novocaine act as Na+ channel blockers, preventing the movement of sodium across the neuronal membrane. This inhibits the transmission of nerve impulses and helps achieve temporary numbness or loss of sensation in the area of application.
Step-by-step explanation:
Local anesthetics are drugs that block nerve conduction when applied locally to nerve tissue. They act on any part of the nervous system and on every type of nerve fiber. Drugs like lidocaine and novocaine act as Na+ channel blockers, preventing the movement of sodium across the neuronal membrane. This effect makes them effective local anesthetics because it inhibits the transmission of nerve impulses in the area, leading to temporary numbness or loss of sensation.