Physiology In a myelinated nerve fiber, refractive period is 1/2500 seconds. What is the impulse rate? A 40 per sec B 250 per sec C 400 per sec D 2500 per sec 💡 Explanation In a myelinated nerve fiber, refractive period is 1/2500 seconds. What is the impulse rate? ✓ Correct Answer: D. 2500 per sec