What are the two kinds of summation seen in muscle fibers 2W

What are the two kinds of summation seen in muscle fibers? (2)Which one of them results in a tetanus? (2) What happens to the muscle if the stimulation is continued once it is in tetanus? (2)

Solution

High strength of contraction of skeletal muscle can be changed to generate greater force. There are several means for the generation of great force. These include the recruitment of motor neurons, absence of fatigue, twitch summation, tetanus and muscle hypertrophy.

All muscle fibers forming a bundle called motor unit. For strong contractions to occur several motor units are recruited and stimulated to contract simultaneously and this process is known as motor unit recruitment.

The absence of fatigue contributing to sustained contraction for longer duration. The contractions with greater tension resulting in the two twitches produced from two action potentials summing into a greater tension is known as twitch summation.

Stimulated muscle fiber does not have a chance of relax between the stimuli and result in smooth sustained contraction of maximal strength known as tetanus. Tetanus is 3 – 4 times stronger than a single twitch. Muscle enlargement with the increase in diameter results in hypertrophy which causes powerful contractions.