What is the difference between tonus and tetanus?

Answer 1

1. Even when a muscle appears to be at rest, a certain amount of sustained contraction is occurring in its fibers. This is called muscle tone. (Muscle tone is a response to nerve impulses that originate repeatedly from the spinal cord and stimulate a few muscle fibers.) A tetanic contraction is when a forceful sustained contraction lacks even partial relaxation.

Answer 2

The strength of summated contractions is always greater than the strength of individual twitches, since twitches are responses to less-frequent stimulations. Summation can culminate in tetanus, a state of sustained maximum contraction. For example, making a fist places the muscles into a state of tetanus.

Another characteristic of muscle function is the ability to achieve muscle tone, or tonus. Tonus is a condition in which a muscle is kept partially contracted over a long period of time. It is produced when one set of fibers, then another set, is briefly stimulated so that some part of the muscle is always contracted, although most of the muscle remains relaxed. Normal posture in the presence of gravity is achieved by tonus. Exercising increases the tonus of muscles used.

Answer 3

A twitch is n involuntary muscle contraction or shorting where the muscle tightens and releases usually quickly and tetanic is a continued or sustained twitch.