Which of the following is a tissue response indicating a sustained muscle contraction?

Which of the following is a tissue response indicating a sustained muscle contraction?

• A. Ion migration
• B. Sensory twitch
• C. Twitch contraction
• D. Tetanic contraction

Answer: (D)

When a muscle is stimulated repeatedly, twitches can sum to create a stronger, longer contraction, and at a high enough stimulation rate the contractions fuse into a single, continuous, smooth contraction. That sustained, fused contraction is called a tetanic contraction. So the tissue response described as sustained is the tetanic contraction. The other terms refer to brief or unrelated processes: a single impulse produces a twitch contraction, and ion migration or a nonstandard term like sensory twitch doesn’t describe a sustained contraction.

When a muscle is stimulated repeatedly, twitches can sum to create a stronger, longer contraction, and at a high enough stimulation rate the contractions fuse into a single, continuous, smooth contraction. That sustained, fused contraction is called a tetanic contraction. So the tissue response described as sustained is the tetanic contraction. The other terms refer to brief or unrelated processes: a single impulse produces a twitch contraction, and ion migration or a nonstandard term like sensory twitch doesn’t describe a sustained contraction.