Question

Refractory period lasts almost the same length as a contraction or ap… preventing tetany.

a) Synaptic
b) Absolute
c) Relative
d) Action

Answer 1

The refractory period that lasts almost the same length as a contraction, preventing tetany, is known as the absolute refractory period. It lasts approximately 200 ms for cardiac muscle and ensures proper heart function by preventing premature contractions.

so the correct answer is Option B

Step-by-step explanation:

The refractory period is crucial in ensuring that muscle cells, such as heart muscle cells, have time to contract properly before another electrical event can occur. The refractory period prevents tetany, which is the continuous contraction of a muscle that can occur with high stimulus frequencies. The refractory period consists of two phases: the absolute refractory period and the relative refractory period. For cardiac contractile muscles, the absolute refractory period lasts approximately 200 ms, during which another action potential cannot be generated because the voltage-gated Na+ channels are inactivated. This is followed by the relative refractory period, which lasts approximately 50 ms, during which a stronger-than-normal stimulus is required to initiate a new action potential.

Through these combined periods, totalling about 250 ms, the heart muscle can complete its contraction cycle, thus effectively pumping blood. This prevents premature contractions that would be detrimental to life.

the correct answer is Option B

Answer 2

The refractory period lasts almost the same length as a contraction or action potential, preventing tetany. Option c) Relative is the answer.

Step-by-step explanation:

The refractory period is a critical aspect of neural and muscular function, preventing sustained muscle contraction or repeated firing of action potentials. It is divided into two phases: the absolute refractory period and the relative refractory period.

During the absolute refractory period, a second action potential cannot be generated, regardless of the strength of the stimulus. This phase coincides with the time when the voltage-gated sodium channels are either open or inactivated, preventing their immediate reopening.

In the relative refractory period, a second action potential can be generated, but a stronger-than-normal stimulus is required. This phase aligns with the period when some sodium channels have recovered from inactivation, allowing for the initiation of another action potential if the stimulus is strong enough.

Option c) Relative is the answer.