Someone argues: "A ventricular action potential lasts about
PHYSICS · Multi-part · Fermi University Physics · Biophysics & Medical Physics · Bioelectricity, the senses and the physics of the body · Bioelectricity, the senses and the physics of the body
Forces, Machines and Signals, Ch Muscle, heart and the fields outside the body
Problem
Someone argues: "A ventricular action potential lasts about 250ms. Skeletal muscle tetanises when impulses arrive faster than the twitch relaxes, so if we pace the heart electrically at 300 beats per minute (an interval of 200ms between stimuli), each new stimulus will arrive during the plateau of the previous action potential. By the same reasoning as skeletal muscle, the contractions will summate into a stronger, fused cardiac tetanus." For this model cell, take the action potential and its refractory period to stay at about 250ms even at this pacing rate.
((a)) Find the error in this argument.
((b)) State what actually happens to the stimulus that arrives 200ms after the previous one.