The absolute and relative refractory periods in ventricles are essential for proper cardiac function and prevent premature contractions. These periods are determined by the state of sodium and potassium channels, ensuring effective pumping of blood.
The absolute refractory period in the ventricles is the period when the ventricles are completely inexcitable, corresponding to the time when the voltage-gated sodium channels are either open or inactivated. It is essential to prevent premature contractions in the heart, ensuring effective pumping of blood.
The relative refractory period, lasting approximately 50 ms, occurs when the voltage-gated sodium channels are closed but voltage-gated potassium channels cause hyperpolarization, allowing another action potential under specific conditions.
The refractory period in heart muscle, longer than the contraction and relaxation periods, is crucial for maintaining proper cardiac function and preventing conditions like tetanus.
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