Qualitative changes in electrical reactions of muscle tissue are:

• A. Sluggish contraction
• B. Hyperexcitability or hypoexcitability
• C. Maximal contraction
• D. A contraction which continues

Answer: (B)

Qualitative changes in electrical reactions of muscle tissue refer to how readily the muscle membrane can be excited by a stimulus—the tissue’s excitability. This is about the nature of the electrical response, not how fast or how hard the muscle contracts once activated. When excitability rises, the tissue becomes hyperexcitable: a smaller or weaker stimulus can trigger contraction and responses may be exaggerated. When excitability falls, the tissue becomes hypoexcitable: a stronger stimulus is needed to provoke a contraction. The other options describe how the muscle behaves mechanically (speed of contraction, maximum strength, or a contraction that lasts), which are not about the electrical responsiveness of the tissue. So the best description of qualitative electrical changes is hyperexcitability or hypoexcitability.