A continuous, sustained contraction that shows no relaxation is called a. Treppe b. Complete tetanus c. Twitch d. Wave summation e. Incomplete tetanus
The correct answer and explanation is:
The correct answer is b. Complete tetanus.
Complete tetanus is a type of muscle contraction that occurs when a muscle is stimulated at such a high frequency that it does not have time to relax between stimuli. As a result, the muscle remains in a continuous, sustained contraction without any relaxation phase. This is different from incomplete tetanus, where there is some partial relaxation between stimuli, leading to a “wavering” contraction, but still a high degree of tension in the muscle.
To understand complete tetanus more clearly, it is helpful to compare it with other forms of muscle contractions. In treppe, a series of stimuli are applied at a low frequency, and the muscle contractions gradually increase in strength, resembling a staircase pattern. This happens because of the increase in calcium availability in the muscle fibers with each successive stimulus, leading to stronger contractions.
In a muscle twitch, there is a single, brief contraction followed by relaxation. It is the simplest type of contraction and occurs after a single stimulus is applied to the muscle. Wave summation is similar to incomplete tetanus, where multiple stimuli are applied in quick succession, but there is still partial relaxation between them.
In complete tetanus, the stimuli are so rapid that there is no time for the muscle fibers to relax. As a result, the muscle produces a sustained contraction that can be maintained until the stimuli stop or until fatigue sets in. This continuous contraction is useful in situations where a muscle needs to maintain a steady level of force, such as when holding a heavy object for an extended period. However, in a real-life context, muscles do not often experience complete tetanus unless they are under high stimulation, as fatigue typically prevents this type of contraction from being maintained for long periods.