Question

One of the reasons why the heart keeps on beating throughout life without fatigue is

• A. it contracts slowly
• B. it has a refractory period
• C. it can use lactic acid as an extra source of energy
• D. none of the above

Answer 1

The correct option is B it has a refractory period

The refractory period is a short phase in time following an action potential where another action potential cannot be generated. Because of this, heart muscle can avoid contractions too close to each other, which can cause fatigue very quickly.