Modestly increasing the frequency of the heart beat from 70 min^-1 to 120 min^-1 will A) Increase the strength of contraction by increasing the size of the Ca²⁺ transient B) Decrease the strength of contraction due to fatigue C) Increase the strength of contraction by initiating contraction before the heart has completely relaxed D) Increase the strength of contraction by stretching the m yofilaments E) Increase the strength of contraction by inhibiting NCX

Question

Quizplus · Accepted Answer

Increasing the heart rate from 70 to 120 beats per minute increases the strength of contraction by increasing the size of the calcium transient. This is because a higher heart rate leads to more frequent calcium influx into the heart muscle cells, enhancing the force of contractions.

Modestly Increasing the Frequency of the Heart Beat from 70