Sympathetic stimulation of cardiac muscle cells produces stronger and faster contractions because proteins that pump Ca²⁺ out of the cell are inhibited,which reduces Ca²⁺ concentration in the sarcoplasm.

Question

Quizplus · Accepted Answer

Sympathetic stimulation of cardiac muscle cells actually increases the level of Ca²⁺ in the sarcoplasm by promoting the influx of Ca²⁺ through voltage-gated calcium channels. This leads to stronger and faster contractions. The proteins that pump Ca²⁺ out of the cell are not inhibited but may be less active due to increased Ca²⁺ concentration.

Sympathetic Stimulation of Cardiac Muscle Cells Produces Stronger and Faster