Which effect occurs when electric current passes through a muscle causing contraction and is used in medicine?

Which effect occurs when electric current passes through a muscle causing contraction and is used in medicine?

• A. Magnetic Effect
• B. Physiological Effect
• C. Electromagnetic Induction
• D. DC Current

Answer: (B)

When current is applied to muscle or its nerves, the body’s immediate response is a muscular contraction driven by the physiological effect of electricity. The electric current depolarizes nerve and muscle membranes, triggering action potentials that cause the muscle fibers to contract. This is exactly the mechanism used in medical electrical stimulation therapies (like NMES) to produce controlled contractions for rehabilitation or treatment. The other terms describe different phenomena. The magnetic effect refers to the magnetic field generated by current, which isn’t what directly causes contraction. Electromagnetic induction involves changing magnetic fields inducing currents in circuits, not the direct contraction mechanism. DC current is simply a steady type of current, not the specific biological response that leads to contraction.

When current is applied to muscle or its nerves, the body’s immediate response is a muscular contraction driven by the physiological effect of electricity. The electric current depolarizes nerve and muscle membranes, triggering action potentials that cause the muscle fibers to contract. This is exactly the mechanism used in medical electrical stimulation therapies (like NMES) to produce controlled contractions for rehabilitation or treatment.

The other terms describe different phenomena. The magnetic effect refers to the magnetic field generated by current, which isn’t what directly causes contraction. Electromagnetic induction involves changing magnetic fields inducing currents in circuits, not the direct contraction mechanism. DC current is simply a steady type of current, not the specific biological response that leads to contraction.