Types of Graded Responses
Fused (complete) tetanus
No evidence or relaxation before the following contractions Frequency of stimulation does not allow for relaxation between contractions The result is a smooth and sustained muscle contraction
Summing of contractions
One contraction is immediately followed by another The muscle does not completely return to a resting state due to more frequent stimulation The effects are added
Twitch
Single, brief contraction Not a normal muscle function
Unfused (incomplete) tetanus
Some relaxation occurs between contractions but nerve stimuli arrive at an even faster rate than during summing of contractions Unless the muscle contraction is smooth and sustained, it is said to be unfused tetanus