In the context of muscle physiology, what is 'tetanus' generally referring to?

Tetanus refers to a state of increased nerve stimulation frequency which leads to a sustained muscle contraction. When a muscle is stimulated at a high frequency, the individual twitches do not have time to relax completely before the next stimulus arrives. This results in a summation of contractions, causing a more powerful and prolonged contraction known as tetanic contraction. This phenomenon is crucial for many normal physiological functions, such as maintaining posture and generating forceful movements.

In the case of tetanus, the frequency of stimulation is key because it determines whether the muscle can relax between stimuli. High-frequency stimulation leads to this continuous contraction, whereas lower frequencies typically result in muscle twitches with relaxation intervals. Hence, tetanus is fundamentally about the relationship between nerve impulses and muscle contractions, showcasing how the muscles respond to rapid stimulation.