The absolute refractory period in contractile myocardiocytes

Question

A,is to prevent contractions in cardiac muscle
B, prevent temporal summation and therefore complete tetanus in cardiac muscle
C,is a time when no other stimulus can cause an action potential regardless of the strength
D,b and c are correct
E,a,b and c are correct

Answer 1

The correct answer is D, b and c are correct.

Here's a breakdown of the relevant points:

• A is incorrect: The absolute refractory period does not exist to prevent contractions in cardiac muscle per se; rather, it is a feature of the action potential that ensures proper timing and coordination of heart contractions.

• B is correct: The absolute refractory period prevents temporal summation and therefore complete tetanus in cardiac muscle. This characteristic is crucial because tetanus, which could occur if contractions overlapped too much, would be disastrous for heart function.

• C is correct: During the absolute refractory period, no other stimulus can trigger an action potential, regardless of its strength.

Thus, the combination of options b and c being correct leads to the answer D.